It isn't. Germans lack their originally intended tank advantage and have to face superior BARS, Brens and Penals so there is no reason they shouldn't get capable infantry. Mind you that this also forces the Wehr player into a doctrine and denies the MG42 upgrade for Grens. The PG utility isn't that much of a deal for a 340 mp unit that lacks the firepower to fight aforementioned allied infantry at range.
Then explain very low USF and UKF win rate against ost in CGS2.
Also, ost always had capable infantry.
But its not "I spam one unit to win" army, its combined arms army.
The one unit IWIN army is OKW there.
There is also this cost thing you know, if opponent got 3x 300mp squads, you aren't going to pay much more for 4x240mp ones and LMGs are going to make mp bleed insufferable.
And what exactly sits in your head to think that mid/low range infantry should be able to fight all/long range oriented weapons/squads?
Sorry, but ost isn't a weaksauce you're trying to make it out to be in terms of infantry.