If your co-workers and management don't care about code quality, you cannot force them to care. If you made a genuine attempt to convince them and you are being ignored, it is not really your role to take it any further.
I'm actually tired of rewriting that awful code on my own.
I think it is time to quietly start looking for a new job. Meanwhile, resist the temptation to rewrite the crap code for reasons other than fixing bugs. And try and get the culprits to fix their own bugs.
Having said that, it is possible that the team lead cares more about this than he is letting on. He may simply not be in a position to take the necessary action to deal with the poor quality culture. For example, if the project is running behind, getting rid of staff may not be an option. Or maybe he does not have any real clout on staffing issues ... and the culprits know it.
