15 bricks crush an ML. 30 bricks crush a mega when it has nothing to retreat to. 22 bricks crush a GC. 21 bricks crush a chicken when it has micro as garbage as mine lol.
Not even sure why you say that closed games come down to T4. If I know where the T4 is coming, I can very easily stop it through mass efficient defenses against it and just keep making my eco sim. This can be point defense, arty, rambo SACUs, air. This is what happens on every canis/hilly/whatever I play that isn't decided by a brutal air crush.
This is also why T3 is so garbage on these maps. Because it's SO bad to make infinite unit spam since you are immediately made irrelevant as everyone and their mom ecos up and leaves you on your unringed t2 mexes totally marginal to the game state. To make t3 spam worthwhile you need a consistent transition between t1 -> t2 -> t3. Or at least some t1 -> t3 or t2 -> t3 aspect. If it's some closed garbage map then you skipped t1 and t2 and will more than likely skip t3 because it isn't worth the lump sum investment. Might as well as scout and abuse defender's advantage by rushing your own t4 faster than the enemy can make theirs + bring it to you. I'm already spamming hives for my quantum gateway for RAS SCUs so why make even more unneeded infrastructure?
This is not a balance problem but rather a map problem.
Actually no, it isn't even a map problem most of the time. Mostly it's just that players are pretty incompetent and can't be trusted to work as one. So you are better off just ecoing up and finding your own sieves to abuse and get ready to capitalize on anything some dude on your team manages to randomly do.
This is why 2v2s are much better to see how serious teamgames would go. You not only have easier coordination but a vast space to interact with which almost always correlates with more variability in strategy. 3v3 and 4v4 are also ok but it requires 20x20 maps pretty much.