[jokethrowaway]

Your examples (while beautiful) are fairly different from each other.

The assembly tricks got obsoleted because they're not needed anymore - we simply don't program in that hardware anymore.

jQuery still works fine to this day. It's just that engineers don't like it anymore. The same will happen to React in a few years.

I wouldn't hire a jQuery developer for working in a cushy company with their millions and their React codebases - React knowledge is actually one of the things we test for (and, unexplainably, one of the few exceptions we'll allow to avoid knowing about algorithms and time complexity).

If I had to build something with my money on the line, I'd definitely pick the jQuery veteran.