Stability is more about not introducing new bugs than reducing the number of bugs in total. i.e. if a system is working well enough for you now, because you can

Stability is more about not introducing new bugs than reducing the number of bugs in total. i.e. if a system is working well enough for you now, because you can work around or are unaffected by the bugs that currently exist, and your requirements don't change, it will continue to work for you in the future, because they are much less likely to disrupt your setup with new bugs or even just changes that require your intervention. Debian is great for that 'throw some infrastructure on a box and leave it chugging away for years' kind of situation, and conversely terrible for the 'actively developing a new product' situation.