Units balance cost and upgrades

There are other tools to balance factions and units early/mid and late game and I wonder why Relic never used them as primary stat for the balance.
If we compare 2 units such as Riflemen and Grenadier, people are most likely to take in comparison their size, buying cost, reinforcement cost, upgrade available and dps stat. But there are 2 others stats that can make the balance work better between the two of them: the upkeep and popcap.
When it comes to balance, I have the feeling people always configure popcap cost of any squad to be the closer possible to the squad size like a 5men squad costing 6 or maximum 7 popcap and the only variable about this is if the squad is/can be considerate as elite or not. When in my opinion popcap should be a complete arbitrary value and only depending on balance wishes: how do we(as game designer) want players to use this particular squad, do we want him to build a lot of them or few of them and what impact on the game do we want from them and at which cost.
Squad Popcap should be completely dissociated to the squad size and unit power and solely depending on Balance and Gameplay meaning.

We know popcap and upkeep are linked and form what I call the macro-economic cost of a unit when the buying and reinforcement cost are what I call micro-economic cost.
What does it mean.

-Micro-economic cost means that a unit with a high buying and reinforcement cost but low popcap cost you nothing if you don't lose any model. You have your squad on the field, you paid for it and until you need to reinforce it, its impact on your economy is low since the upkeep is low.
-Macro-economic cost means a unit with a high popcap and upkeep cost but low buying cost and reinforcement cost impacting your economy over time (mp income reduced by upkeep). Until you start losing models and thus reducing your popcap the unit cost you manpower by affecting your income.

In other words, a Micro-economic unit is more related to Elite unit you need to keep alive at all cost and lose a little as possible models and a Macro-economic unit is related to your backbone infantry requiring your to use them in order to balance their over-time cost. (An Elite unit is most likely going to have both Macro and Micro economic cost high, this is an example)
You can keep your elite unit for ambushes and use it supportively.
Your backbone infantry need to be used as much as possible to mitigate its upkeep cost.
In practice, what does it means. Let's imagine that Riflemen squad popcap is 10 but with a lower buying and reinforcing cost than today. So buidling 4 RM brings you to almost half of your army population, + 1 Rear echelon and lieutenant and you go over 50% of your popcap. In order to keep your army viable and mitigate this cost you need to have your squads always fighting and pushing the enemy lines.
Now something important to note is every time you retreat a full health RM squad, you are losing manpower, the time to retreat + the time to get back to fight make you lose manpower via the high upkeep associated. As opposed, retreating a RM 2men squad cost you much less until your reinforce it. Macro Economic units are more impacted by suppressive fire in term of economy.
This mechanic of increasing popcap is particularly interesting to reduce the blob power. Continually blobbing 4-5 squads with high popcap and retreating as soon as you meet an HMG suppressing you but not killing so much models make you lose manpower via their high upkeep. Going full Riflemen, like 5 or 6 squads would be an over-kill for your economy. Even if you lose many models in the battle, your low income would not allow you to reinforce and develop furthermore your army.
In practice, this also requires some adjustment in teching and tiering. if 4 RM squads take you 40 popcap, how do you bring your army to the late game? With upgrades, in any forms, building each tier could reduce the upkeep cost, veterancy as well and finally some special upgrades to buy at specific tiers. Having a lot of Riflemen could be a strategy but costing you the price of an upgrade on T3 to be viable on the long run, a price that can includes fuel and so forcing you to take strategic decisions.

Those strategic decisions would happen at each tier of the game in case of tier upgrade. The player would have to think where to spend his economy. To reduce the impact of his early game units or to invest directly on the next tier unit with the possibility of "bankrupt" if it goes bad.

Interesting theory, though it'd only be strategically valuable if factions had ways up upgrading/mitigating the upkeep or popcap of these units, or else it's a limiting factor that players don't have much control over.

I prefer pop cap and upkeep be linked with territory control. That I think worked much better as it was in coh1. I know a lot of people tend to dislike it, much like CoH1 wehrmacht vet, but I think they were crucial to gameplay. For coh2 it could work where pop cap may not even have to be limited by territory, just impact on upkeep.

Also, in that vein, repairing should inflict some manpower upkeep. Not sure why that isn't the case in coh2.

Both can be associated.

Boring that this game dont have upgrades choices. Its only one certain upgrade for units.

This is one of the main issues of coh2. vCoh had better logic of upkeep and upgrade.

All upgrades to infantry (vet for axis and bars for allies) were made through fuel investment. In the case of riflemen the more rifles you had higher the upkeep was so needed to invest fuel in order to reduce it. To sum, strong infantry meant not fuel to tech or rush out vehicles and weak infantry was equal to get vehicle earlier. All decisions had strong and weak points, same with risk or safe play. In coh2 you can have strong infantry and rush a vehicle at the same time and there core infantry which is always weak no matter what you do (f.e. cons).