It inflates the cost and that is undeniable. Purchase price of cons and grens are the same but the fact that if you say, go ostroppen in the preview your tech costs are the exact same as if you go grens but if you were to (for some reason) spam CE and never build a single con you would save resources on tech means cons are more expensive.
CON tech is a cost that only affects cons. They are linked. If you build no cons you do not want to get these techs. If you build cons you probably will. The costs are linked. If you build only 1 con, the techs may not be worth while as they inflate the cost of cons. If you don't build a con squad until you have heavy Armour on the field they will not be fully equipped and require additional investment to get fully kitted
If you never build a single gren you will still tech up. If you build only grens you will still tech up. If you build 1 gren teching up is still cost effecient for kitting out grens. If you don't build a gren until you have a tiger out you have spent only 240mp and have everything you need (obviously discounting weapon upgrades) for them to function. You have no additional costs. 240mp covers everything.
Your argument actually work the other way around.
If one does not build a single conscript one can save the AT grenade/molotovs.
If one does not building a single grenadier will still have payed the cost for faust/riflegrenade/lmg that is included in Ostheer tech cost.
The only way to actually be accurate in comparing the tech cost across the different systems is to calculate the total cost used across the whole game and assigning to the units used during the game.
But all of that is not very relevant. The simply fact remain that Ostheer do not actually have an early advantage because of tech.
4 conscripts builds work just fine but 4 grenadier builds do not work.
The argument that grenadier are cheapest mainline infatry (they are not) and ostheer have an advantage because of that is simply mute.