Actually average bridge can take 30 ton tank load with no problem. And VT5 is around 30 ton. DOT standard is around 40 ton
I said VT4 not VT5, and I gave an estimate 40% of Bridges in general. VT5 is a light tank that is a different category of Tank. If you want to count that then you start with Type 59G, T55, CV90120T, PL01 concept, FNSS PT Pindad Modern Medium Weight Tank.
In summary how many MBT weigh in at under 40 tons????? one T64 and some upgunned T55 variants that's it. and even then they are leaning to 40 tons class.
Sure there are a few in the 40 ton weight Class T84, T90, Type 10, PT91,Type 96, T72... but other than the Type 10 ( and some argue that as a light tank) most of these are the base weight without armor add ons or older versions.
So the problem is not unique. All MBT happen to fit in that excessively heavy category including VT4 and Type 99 and Type 96. Both Versions of the Arjun the Mk1 at 59 tons and the Mk 2at 68 happen to fit this to.
Arjun was always a limited order, the Fact the T90S Bhishma was being Ordered in massive numbers alongside small batches of Arjun was pretty much proof that the Indians never meant to make it their main line MBT. They ordered something like 1200 units of the Russian tank.
Unless India wants to give up self-sustainability, the military should continue to purchase domestic weapons in small batches. If they stop, it will be harder to build the industry as time goes on. Already some of the weapon system is too complex for a mid sized country.
Indian self sustainability though is a bit dubious. there track record is shaky, Arjun uses Israeli and Russian Technologies as well as some oddities in a modern MBT. The main gun is a 120mm rifled gun, this gun is mostly out of fashion. The British who still use it tested it against the Nato Standard 120mm and found it wanting, the only reason they did not change the Challenger 2 was that the Ammunition stores in the Challenger 2 Would have required a massive redesign.
As I pointed out above the Indians only intended a small number of Arjun tanks. Ordering large numbers of T90S at the same time. The Indian Insas is considered a deeply flawed rifle, Although based on a number of proven systems the AKM, FAL, HK designs, yet Quality control and manufacturing materials proved wanting with on again off again replacement programs.
I mean it seems like licensed production seems to do better for them.