Do front-end devs really not know this sort of thing in 2025? I haven't done serious web development since the jQuery days and it's still second nature to me. (Granted, WebP barely existed at that point.) Honestly, when I was growing up this sort of thing was something ordinary users would know about.

In the days of jquery, it was much more common for people to worry about file size and load time. With faster mobile internet, there are less incentives to learn about image formats and their benefits. Many developers coming from bootcamps often lack this knowledge.

I'm sorry but they do not. React is used as a cargo crutch for web development these days. Its necessity is not considered for problem solving, it is simply assumed as needed, based on learning by rote. What you now have is a legion of web developers who pay little attention to optimisation both within the framework and in general without.