Infantry, either light dismount or heavy infantry, cannot be replace by tank for few reasons. Tanks cannot take and hold terrain and building. And, infantry are one of the most effective AT unit presently. I remember an exemple, the Israeli 190th Armoured Brigade (commanded by Assaf Yagouri, a famous Isreali tank commander) was ambushed in the desert in 1973 by the Egyptian 2nd Infantry Division. The 190th Armor have 120 M60 US-made MBT, which was one of the best tank back in this time and this unit was one of the finest Isreali's tank unit. The Egyptian 2nd Infantry didn't have any armor or artillery support, only lot of AT-3 Sagger. The entire 190th Armored Brigade was destroyed and his commander captured... Infantry can still beat tank...
Some US M1A1 or M1A2 was actually killed in Iraq by infantry... They just hide, and when the tanks bypass them, shot at the rear of the tank with AT missile.
Well, I said it before, tanks are only good at conventionnal warfare. But the combinaison of multiple task LAV can also be effective. I give an exemple. There a unit equiped with some Coyote Recon vehicule, some LAV-III, some MMEV (is not yet in service, but I'll take the same performance as a ADAT since it's a wheeled ADAT) and some LAV-TUA. The ennemy have some heavy tanks. Even before the battle begin, the Coyote are able to detect your comming attack, after the MMEV will fire their AT missile (which have a penetration of 900mm) while the tank are out of their gun range (since the missile on the MMEV have 6km of range) If they come in the 5km range, the LAV-TUA will add firepower. So think about this... The Canadian LAV are made for battle information dominance, we know where are the ennemy even before they spot us... And coordinate a few unit together, will make a powerful combat task force.
Canada have some of the best LAV in the world.
A Infantry Division with no support can certainly beat a Armored Division. Believe me, I'm myself an infantryman. Give to the infantry division some LAW, some ATGM. And they will be able to destroy a massive armor attack. BTW, an armored division generally have around 290-350 tanks, but there's always infantry in the division. For the sole reason that only infantry are effective of detecting and fighting infantry.
I received a anti-tank formation with my soldier formation. I used mainly the M82 Carl Gustave in my training. Even this is an old weapon and cannot pierce a modern MBT front armor, thoses rounds can pierce the rear armor and dommage some important pieces like tracks or aiming device. We also have the M72 LAW, which is more effective. Give a few LAW to each fireteam, and 1 or 2 ATGM per platoon (Canada have the TOW 2 and the Eryx), their firepower is sufficient to take out a tank platoon. I remember, in a combat exercise against US National Guard (US National Guard was our OPFOR, was an exercise US National Guard vs Canadian Army Reserve), two fireteam, (my fireteam and the 1st fireteam of my platoon) "killed" 4 Abrams tanks with our weapon and we also took out the entire infantry platoon that was accompygning them.
Still, I'm reapeating myself since the beginning, tanks are made for conventionnal warfare, and LAV for asymetric warfare. The different is that LAV can be adapted for conventionnal wafare, if you coordinante your LAV correctly, this is the reason why we are developping the ISTAR communication system.
Armour cannot hold ground, while infantry can, and infantry can flush out survivors of tank attacks that the tanks can't get to themselves. Alternatively, infantry certainly cannot produce the shock effect that armour attacks can produce if a break-through has been achieved.
That said, and speaking myself as a former infantryman, while the Infantry may the the Queen of Battle, the tank is still King of the Hill. It takes a lot to kill first-rate tanks in the hands of competent crews - and you can pretty much forget about taking out any NATO MBT with composite armour. Yes, there are anti-tank weapons available to the infantry that can penetrate those parts of the tank that lack that composite armour (concentrated along the frontal arc of the tank), especially top-attack weapons.
Something like US Javelin is one of the few infantry anti-tank weapons that may give infantry a real fighting chance against armour under conditions of sustained high-intensity warfare, provided that the tactical situation gives the infantry at least several hundred metres (absolutely no less than 500m and preferably a lot more than that) distance between them and the armour (and their accompanying infantry) so that the defending infantry can get at least one volley off before the tanks are on top of them (literally). There are a few other weapons that are top-attack, but most of them don't have the potential range (let alone fire-and-forget capability) of Javelin.
As for the other infantry anti-tank weapons, unless you're in the right place at the right time, and you get a quick shot in at the side or rear of a passing tank, they're pretty much suicide weapons (against tanks - they can can be real lifesavers against machine-guns, trenches, bunkers, other armoured vehicles short of MBTS, etc.) Very few infantry have ever lived long enough to get a shot off at a tank, and even fewer have lived long enough to tell the tale. The tanks have machine guns and a lot of crews know how to use them - even to the point of spraying each other's backs when the infantry get especially thick. But chances are the enemy infantry escorting those tanks will quickly gun down anyone who gets off a shot at a tank, and very rarely do those shots hit, let alone do real damage.
Tanks can see targets through their sights at very long ranges under ideal conditions, and even some older tanks like the M-60 A3 were capable of hitting targets while stationary at 5,000m with 105mm gun - there are some Israeli claims that Merkava can do the same out to 6,950m. More modern tanks like M-1 A1/A2 with 120mm gun in published claims can hit out to 3,200 m while on the move, and there is speculation that it is a very good deal longer than this in the right hands.
Tanks can dominate the ground in both open and close country, which is why tanks are used to support infantry even in street fighting. The tanks can surge forward suddenly, take out a machine-gun or rocket team with its main gun that has prevented the infantry from moving from block-to-block and then surge back, knock over walls to allow the passage of the infantry to the rear of buildings, and patrol roads and highways in close terrain to keep lines of communication open while the infantry engage the enemy up in the hills (ie Korea) or in the depths of the jungles (ie Vietnam). Tanks save a lot of grief and loss for the infantry.
This is why, when first light vehicles were found to be too vulnerable in Afghanistan, and the troops there received LAV III Strykers instead and yet these were still found to be too vulnerable and with too little crushing power and firepower (especially after a platoon of the RCR was lured into a Taleban ambush in a village, and the troops were pinned down, took heavy losses, and couldn't get out), the Canadian Army brought back the old Leopard 1s (which were being taken out of service to be replaced by an assault gun version of the Stryker). The Leopards can crush most walls and buildings found in Afghan villages (and spare infantry ruinous losses trying to get over or around those obstacles), take out enemy emplacements with main gun fire, again sparing infantry the burden of having to assault those positions themselves, and dominate the ground in a way that no armoured car ever could. And all this in an unconventional "guerrilla" war.
By the way, upgraded M-113A3 tracked APCs are being sent to Afghanistan to replace more of the Strykers, because the Strykers' wheeled suspension can't take the rough terrain of Afghanistan and the hulls are cracking. Not to mention that M-113 A3, though quite old, is better able to resist roadside bombs and RPGs than the Stryker is. And the Canadian Army has ditched the Stryker Assault Gun and is buying Leopard 2s.
