As a dev who cares about UX, this is crazy to hear but resonates, I've got a few weird looks from people whenever I mentioned some URL improvements. I've also worked with people who understood it. I've seen a correlation though, when people cared enough I could share freely about this, when I did the designer's and dev work I would just add that in (I'm def not a designer, so if I'm doing design work that means the owner doesn't care about design, let alone URLs).

I can imagine in your situation as a pure designer how you got it though though, sorry to hear that and I wish other devs cared more. I've def mentoring people to care about it so hope others do so too.