As a former TL, I can say that I constantly went after the worst TMs we had. I tried to get them out the door. Two things happened.
The first was a road block known as the ETLs. For example, when I was a GSTL I tried my hardest to get rid of cart attendant. The guy disappeared for hours, constantly let us run out of carts, outright refused to do the trash/restrooms, etc. Basically - did not do his job. Every single one of the ETLs at my store wouldn't let me do anything about him. All they would tell me was "Blah blah... if we get rid of him, guess what? We will just hire another one exactly like him and waste everyone's time. We can't get anyone but high school drop outs to do his job, so the next one won't be any better". So in other words, the ETLs wouldn't let me touch him.
The second was that some TMs were damn good about covering their tracks. They "knew the game" so to speak. Once they realized I was on to them, they learned how to make it difficult for me to get anything on them. I hate to say it, but it was actually good team members who protected them. Why? They refused to tell me what I pretty much knew was going on but couldn't get solid evidence because I wasn't there to see it. Unfortunately, TMs who were there to see it refused to admit they saw it or knew who was doing it.
Eventually I gave up out of frustration, and honestly that is what happens to most TLs. They really do try to get rid of these people, but eventually after trying countless times and nothing happens we are forced to give up. It just becomes a waste of our time.