After recently doing a lot of work on a system that takes user-originated images for the first time in a while, this has started to become my go-to check. I shouldn't have been surprised at how common it is, but I was and I hope from now on I'm thinking about optimization as soon as user-provided media comes up.

I also think the tooling-takeover on the front end has had a real effect; it automates away decisions at development time in situations where you usually have ideal connectivity. Then when you're doing QA and realize that the site's heavier/slower than will work for some user-device profiles, you face sunk costs for decisions you didn't even really make so much as implicitly invoke. Possibly getting better as tooling gets less naive and more sophisticated about shaking out unused code, but I worry there's also a Jevons paradox that can come into play (your tooling is good at automatically optimizing out stuff you don't use? You might automatically use more of other stuff!).