It doesn't only effect campers. It effects lots of late-game teamgames including 2v2.
The extra pop that you can use to squeeze in one more Jackson/Scott/pershing/calliope can make a huge difference. When Axis has around 90 pop cap they can't get another vehicle but USF can for no apparent reason. Why not fix this? It's not fair or intended.
If you pretend this is just an issue effecting "campers" you are just ignorant. Obviously if the USF player isn't playing well and losing all his units all the time this is a non-issue, I am talking about players with good unit preservation that don't get outplayed all the time.
And I personally remember a lot of games in 2v2 that were basically won by USF flexible pop cap. Just because it's next to impossible to counter 2-3 Jacksons + Pershing/Calliope + 2 Scotts + bar blobs with 100 pop cap axis armies.
