Bad players will always find ways to put the team in a bad position, otherwise they wouldn't be bad players!
If one wants to win, discard ego and figure out the strategy that makes the team win.
If the less flexible players:
1. Stay in the backline and build eco only, go on the front and take and hold
2. Stay in the backline and build big stuff, go on the front and take and hold with no reserve for escalation
3. Go on the front line with spammy units: bring artillery to take advantage of situation, support reclaim and econ, or double down for full on breakthrough if possible
4. Go on the front with artillery: bring screening support, vision, counter assault, anti-counterbattery (cloak, shield, silo, terra), as well as counter opponent antiartillery strategy (anti-terra, placeholder, snipe "anti-arty tanks" with assault like gauss)
Alternatively, one can pursue a micro intensive combat strategy, as opposed to a metal heavy one. The metal can then go into eco or escalation.
That said, in small teams it is quite easily possible to have impossible to carry teams because the teammates choose a bad strategy. Then again, with random draws sometimes it is the other team that ends up with impossible to carry situation and one just try to win the games that is winnable.
Random team games are interesting because the right play is less obvious, there is few ways a single player can "force" the direction of the game into a well explored direction. If bad players have less influence, the game state collapses into a far fewer optimal progressions.
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I am reminded of a recent game which was won by throwing everything into dirtbags and spiders to stalling opponent off mexes until kids finished building 2 pala and hercs before moving out. It wasn't pretty but it worked.
There was also games where the entire game was helped by force firing various unspotted mexes with a few impaler and rebuilding mexes. I think that resulted in a tens of thousand extra metal by the end that enables the lower ranked players to out attrit the other side.