If you can leave your job in a state that means the next 6 months are problem-free then you are amazing. You've obviously planned ahead, documented things, and foreseen potential problems that you've mitigated ahead of time. Any company would be crazy to lose you.
If you leave your job in a state where the problems are fixable then you're pretty good. You haven't foreseen things or left good enough plans, and maybe there's issues with documentation and strategy, but things were in a good state that others can recover from. That's more than most companies ask for.
If you leave your job and everything falls apart then there are issues somewhere. You, or people you rely on, are basically winging it, and the company doesn't see that as a problem.