Also, volks are stronger in early game then cons, so what's your problem here?
No-one said that there is a problem with their scaling. Problem is the power cons receive the second they unlock and get SVTs. Their late-game performance is alright, because there are more units to face them be it armor or elite inf.
Problem is that for a 60 muni upgrade on a faction which spends muni mostly only on mines and AT nades, its just too good for its timing, considering that SVTs put you in a possition of being able 1v1ning both volks and grens.
On top of that allowing cons effectively engage them at all ranges outside of melee + in late game you will be stronger then them.
Sure single Bar might provide more DPS, but BAR is locked firstly behind a fuel cost (which you need to get medics\LVs) and secondly it comes for the more expensive squads of a muni starved faction. In other words USF have a lot of consequences if they deside to rush Bars the second they can.
Soviets on the other hand pretty much pay with 2 layed mines (which most likely will be triggered by enemy inf)\2 zis barrages\1 flamethrower, but all those choses are purely AI ones so in a global picture you didnt sacrific anything, because SVTs will give you stronger AI out-put then any of mentioned options strate of the bat.
Nothing is wrong with soviets having stronger inf early on, but right now SVT cons are just too strong not in late game but in early to mid game.