Yeah makes sense. I wish there was a FOSS UX design philosophy that had caught on. For app design, the Unix philosophy has driven development even to this day, although not as popular now as it once was.
We sort of have bits of it, with the GTK framework and KDE styling. But those ecosystems don't extend outwards enough, and still allow far too much leeway to the UX design to ensure nice looks/function.
Maybe the nature of the widely distributed development makes it overall impossible. The goal of FOSS makes that kind of universal look and feel largely impossible. Heck, even Microsoft can't get that to happen in their own OS. There are many applications/utilities that look pretty much the same now as they did on Windows XP or even earlier.
The general attitude of function over form in our community also makes it hard, and I get that. Especially with limited dev resources as you pointed out. Would you rather have better functionality, or a prettier interface? Tough choice sometimes.