Reddit has a whole other site if you go there without being logged in. That one is built with web components.

The "normal components" you're referring to are just elements. I don't see the need to track a ratio there. All of YouTube desktop's components are web components.

Reddit doesn't use web component on all pages yet. They have them on certain types of comment pages now and are incrementally porting the rest of their site from React to web components with Lit. They've also built this year's r/place with Lit, and are building other things like embeds on web components.