If grenadier are the "cheapest" mainline infatry than they are simply list cost efficient infatry because 3-4 conscripts, 3-4 riflemen, 3-4 tommies are all viable strategies while 4 grenadier is not.
That's not how efficiency works.
Ostheer are probably one of the factions with slowest starts (unless they go doctrinal) so repeating the "cheapest argument" means very little because it does not really translate to an advantage.
Its not supposed to.
That's how balance works.
Different factions have different opening build orders.
Opening with sniper as soviets will never have same impact as opening with sniper as ost.
So I suggest we stop with this myth.
Then stop pretending grenspam should be on pair with mainlines that do not have instant access to best HMG in game and all AI support weapons in a single, cheap, fast to build building.
Viable grenspam is a myth.
Each unit has a cost to buy and the price of grenadier is 240 which is the same as conscripts.
True.
Just as true is that side upgrades that affect cons exclusively inflate cost of cons, while nothing inflates cost of grens, because there is nothing you can pay fuel for that affects them exclusively.