In practice, my experience is that this ends up with only old versions of things in the stable package repos. So many times I run into a bug, and then find out

In practice, my experience is that this ends up with only old versions of things in the stable package repos. So many times I run into a bug, and then find out that the bug has been fixed in a newer version but it isn't updated in the stable repo. So now you end up pulling an update out of band, and you are in the same boat as before. I don't know how you avoid this problem