I feel like it would be even worse on a smaller display where screen real-estate is at a premium. I am fortunate to be able to afford (relatively, compared to most of the world) high end computer equipment where wasting pixels is not as problematic as it might be for someone with less resources.
Ditto. First thing I do when setting up firefox, the default is just way too unnecessarily large.
A large monitor isn't even necessary, it's too large at every monitor size between 13" and 34" (which is the range my personal hardware covers).