Walt would have just cooked with Gale for Gus, made a few million, and stopped.
Did we watch the same series? One of the biggest themes was that Walt was "hooked" on being the king of meth. On being "Heisenberg". That temporary pause with the carwash never would have lasted no matter what happened.
And, yes, Jesse was weak. But he was also a kid who at least had an ounce of empathy for other people. He was capable of real human connection. He was just fricked up. He wasn't a sociopath like Walt.