It doesn't really solve the issue, it's just a nerf.
Its far from cost effective. pg's with shreks or RE with zooks do way better job dealing with tanks then volks with shreks.
There is nothing cost-inefficient about a decent line infantry squad able to do some good AT that doesn't entirely hamstring its AI.
Sure, Schreck PGs and REs with Zooks will do a better job dealing with tanks, and they will also be far more useless against units like upgraded Rifles/IS/Shocks, which are pretty much guaranteed to happen as tanks are, which is why Schreck Volks blobs happen while doing Schreck PG blobs is just shooting yourself in the foot.
Thats the problem, Volks are meatshields and AT.
No other use of them.
They're like Scripts if Scripts didn't have a vehicle snare for an critically valuable purpose to their positioning and they instead just right-clicked vehicles all day.