You mean having 5 levels of veterency compared to the other factions 3 and a Panzershrek isn't enough for Volksgrenadiers to scale into late game, what?
The massive buff to other basic infantry scaling with received accuracy made the bonus's Volks receive from Vet 5 largely pointless. In general Brit units also have much more powerful vet.
Really it's actually quite funny (and by that I mean depressing) how many people are jumping through hoops ITT to try and justify Volks poor performance or just even OKW's poor performance in general (LeiG spam excepted of course).
Currently Volks get the least received accuracy with Vet of any basic infantry in the game. Doesn't it seem weird to you that a faction who's supposed to have superior scaling is easily out scaled by every other faction in the game?