Sure I understand you train against likely threats. But this also makes your statement about ATGMs quite hollow. You're saying a previous generation ATGM system is not very effective against a system that was probably designed to counter it.
How is my statement hollow? I don't quite understand what you are saying. If you read the report on the MAIS Trials that I provided the link to, you will find that most engagements took place at ranges of 1,400-1,700 m. The LAV-III Strykers found that their 25 mm cannon could penetrate the BMP-2 at those ranges, but the 30 mm cannon of the BMP-2 couldn't penetrate the front of the LAV-III until around 800 m or less, forcing them to use their ATGMs. The LAVs in turn countered the use of the ATGMs by closing within 1,200 m of the BMP-2s, but staying out of the 800 m lethal range of the BMP-2s 30 mm cannon while remaining close enough to kill them with snap-shots from their own 25 mm cannons, whereas the BMP-2s had to rely on slow-moving ATGMs at the same range. It was tactics as much as technology that gave the Stryker the edge over BMP-2.
The tactical problem for all ATGM launchers and ATGM-armed vehicles is that in an otherwise more or less level contest, the deck is usually (not always) stacked tactically in the gun's favour
vis a vis the missile. A tank gun or IFV autocannon can snap-shoot and send a sabot round towards its target at a mile-a-second; an ATGM launcher, man or vehicle, cannot, at most a few hundred metres per second. One-on-one, the gun usually beats the missile, especially since missiles often don't get to use their range of a few kilometres due to terrain or bad visibility (something that even the best sensors can't always negate).
If a TOW-armed vehicle had been placed in the same tactical situation as the BMP-2s, for example, it would have fared no better given the typical engagement ranges of 1,400-1,700 m. The problem for IFVs is that they have no recourse other than to ATGMs for weapons that have any chance, however, remote, of a head-on kill to a current-generation MBT. Even most Infantry anti-tank weapons exist at least as much for the psychologial value as for any actual anti-tank capablity the may have. Tanks are usually very hard to kill, especially head-on, and most of the time that's the only part of them that the enemy gets to see and shoot at.