I am not gonna bother going through the argument in its entirety, however, Conscripts are not merely "equal" to Grens in the earlygame, they are quite superior. Without upgrade Grens do not have the dps to keep Cons from closing the disctance - which won't even be necessary in the first place, depending on the map. Conscripts are more survivable, more mobile (Hoorah), can deny cover/buildings at the very cheap, and most importantly, can create their own green cover.
That by the way, is ok, since OH T1 offers the support to rectify Gren inferiority, but lets stay realistic.
Well, if they had it, then grens would be superior as they'd be able to win engagements effortlessly without exposing themselves.
Saying the cons are quite superior is also misleading.
1 gren vs 1 con, sure cons might win that, but 2 grens vs 2 cons, gren DPS becomes potent enough to seriously cripple one of the con squads on approach.
Cons being able to build cover doesn't really help them much.
They are mid/short ranged unit with bad long range DPS, not exactly the type of inf you'd want to sit behind the cover at far.
You can't say the cover denial is "cheap" because its a side cost of 125/25, that isn't really cheap, especially compared to the side costs of axis for similar convenience.
Also, grens have HMG support right from the start that keeps cons at distance.
1 HMG and 1 gren will usually win against 2 cons unless you got jumped on.
You can't really say just grens vs cons, because Ost doesn't rely exclusively on grens and ins't balanced to do so. Cons can work alone slightly better, but they'll fall short without elite infantry or tier support really quickly.