I'm always surprised to see bugs like this where an extremely easy to test part of the spec just seemingly isn't tested and ends up as a bug that never gets fixed until many years later.
The way I've seen it implemented at a small company I worked at before was to explicitly endorse the "20% time" idea that Google made famous, where you may choose your own priorities for a fraction of your working time regardless of the bug tracker priority order. Even if in practice you don't actually have that spare time allocated in your schedule, it does give you some cover to tell your manager why you are prioritizing little UI papercuts over product features this week.
Not really. It's hard to see the difference from the outside without actually digging into it first, but in my experience while there's plenty of "easy" bugs that aren't actually easy, there's also plenty of easy bugs that are actually easy and that apparently everyone else assumed they're not, or else they would have been fixed already :P
Whether or not you fix a bug weighs on the scale against the cost of all of the above things, the cost of time, the cost of these people's attention, and the opportunity cost of them doing something else. And these costs tend to not scale with the size of the pull request. They're fixed costs that have to be paid no matter how small an issue is.
I work at a BigCo, and occasionally get comments from developer friends about "Hey, why doesn't BigCo fix this obvious bug I reported! It's simple! Why are you guys so incompetent??" I look at the bug internally, and it's either 1. got a huge internal comment chain showing it's not as simple as an outsider would think, or 2. it's indeed trivial, but the effort to fix it does not outweigh the costs I outlined above.