Because:
1. SU get a top tier mainline with penals (say what you want of their price, they dominate regardless, they shoud be cost innefective yet they dont)
Except massive bias, you have something else, perhaps valid, to base that on?
2. Contrary to common belief riflemen are top tier also, though ealrygame is their weakest spot, once vetted and upgunned they solidify and commander squads give the minimal support they need.
So top tier they needed to be buffed now?
3. Volks have been target of rightful complaints of their performance, their original design was a mixture of conscripts and grenadiers and this proved to be too effective, nerfing them into the right spot leaves a big enough gap in the mainline department of OKM
Their first iteration was con-gren mix.
Their current life iteration is beefed up grens without a range they would underperform at.
Also, their performance got completely untouched, they simply got a cost to match that performance, so that as well isn't an argument.
Possible solutions are either buff Luchs timing and power or to enable a new opening with obers without upgrades.
That makes no sense what so ever no matter how you want to look at it or how you want to explain it.
So set aside ranting and start using that thing between the ears to understand
Take your own advise and stop ignoring the fact that penals arrive late and are always outnumbered, warranting their performance and, if they were cost inefficient as you claim they should be for whatever mad reason, they would require to be buffed.