Game can't be balanced around 3v3/4v4. Too many variables to take into account. However this can be considered a bug, just make it so you can't recrew vehicles if it takes you over pop cap - problem solved.
True, but Relic cannot also just say 'it cannot be balanced around 3v3, 4v4' and not keep it in consideration or try balancing.
Sure game is to difficult to have perfect balance for 4v4, but a lot of things can be fixed to work in 1v1 and be fine for 4v4 as well (with little effort)
Not having situations where some game modes are completely broken. That cannot be good for player base nor longevity of franchise in long term.
After all a lot of people play team games, skirmishes, etc.
Where there is will, there is a way too.
edit; Speaking in general, not discussing current balance or state of balance in 4v4 or any other game mode