Which is a bit silly, to be honest. I understand wanting to see some credit given, and it wouldn't have cost Vercel anything to do so, but this is hardly "new Remix technology" that they're copying (also the condescending "React czar" stuff is just super inappropriate, but par for the course with the way the Remix team has been talking about Remix on Twitter since the days when they were boasting about not taking VC money).
The fundamental approach Remix (and now Vercel) takes to nested routing with React SSR is fairly straightforward. It's how everyone else (not using a framework) has been doing nested routing with React SSR for, what, at least 5 years? Granted, most of us have been using React Router for our React SSR setups, and credit very deservingly goes to the React Router guys (who are now the Remix guys) for that. Remix did a great job of delivering a framework that (via a nice compiler and file structure conventions) makes this React SSR routing architecture very easy to use! But that doesn't mean that anyone else who takes this same fundamental approach is somehow copying Remix. The home-grown React SSR setup I've worked on for the last 4+ years has been doing the same thing this whole time, and while we might be "copying what the React Router community was doing 4-5 years ago," and that might even include demos or articles written by someone who went on to found or work at Remix (again, really, thanks!), I don't think we're in any sense "copying Remix."
edit: Well, I just noticed on Twitter than the cofounder of Remix (also co-creator of React Router) is, contrary to the opinion I expressed in the paragraph above, clearly claiming that he believes Remix deserves attribution for any usage of concepts which ever existed previously in React Router. I don't agree with this. https://twitter.com/ryanflorence/status/1528862791490105344