Do they?

In my experience a large bunch of packagers are fairly absent, with their patches often causing more issues than they solve and them offering essentially zero support. Want to file a bug report? The Ubuntu packager doesn't respond, the Debian packager isn't interested because you're not using the Debian version, and the upstream packager closes it as "can't reproduce" because the issue doesn't happen with the original source - provided it wasn't already fixed five releases ago, of course.

I've submitted full bug reports with patches fixing them to Ubuntu, just to see it get automatically closed a couple of years later as the version is no longer supported. Nobody ever looked at it. Using self-compiled upstream code and hitting an issue? When I file a bug report directly upstream it's not uncommon to get a fix a day or two later.

There's a reason Flatpak & friends have gotten so popular: a lot of people just want the upstream version. No weird patches or changes, no ancient versions staying around because some new dependency hasn't been packaged yet.

Obviously we shouldn't be harassing upstream developers for not writing patches fast enough, but let's not pretend that the traditional packaging system was/is perfect: it works fairly well for the base system, but it falls apart pretty quickly when it comes to more obscure packages.