I'm thinking more about a 'soft lock-in' situation: the developer writes bad code, but not as bad that you need to start over or stop using it. Just bad enough

I'm thinking more about a 'soft lock-in' situation: the developer writes bad code, but not as bad that you need to start over or stop using it. Just bad enough that only they will understand it and other people who try to contribute will get mad and waste a lot of time and effort to deal with it, so in the end, the bad developer continues writing their shitty code because no one else wants to get involved (and there are plenty of opportunities elsewhere).