I suppose that also depends on the DM's breadth of interest in where the campaign might go and what might happen when it gets there.
For me the loss-of-interest shut-it-down tipping point comes if-when the players decide to have their PCs quit adventuring and become business tycoons, then expect me to work out the economics of it all. Fine for them, but someone else can DM it.
A reaction that I honestly don't understand a lot of the time.
I mean hell, part of the appeal of playing a game like this is that, if you want, you get to do the stuff and be the people you'd never even think of trying to do/be in real life. You can be a fantasy Mafia don(na). You can be a fantasy sellsword with no regard for any life but your own. You can be a fantasy assassin. You can be a fantasy second-story artist who doesn't care who you steal from. You can be the person (or party) who kidnaps the prince rather than rescues him. All of those are evil.
And all of those are IMO perfectly playable.
I'm not suggesting every character every time has to be a complete psychopathic whack-job, but denying evil PCs entirely always strikes me as overkill.