You're right, but that doesn't mean those assembly programmers are suddenly forced to write React.

Being an expert at assembly probably means you're an expert in low level programming. We still have a need for those people, because they'll probably also be able to write C/C++/Rust/Zig/etc very competently.

I consider myself pretty competent in C(And C++ to some degree), and I have a pretty good understanding of how computers work on a lower level, but if you ask me to write React UI components, I probably wouldn't fare well. I understand Javascript/Typescript, sure, but I'm just not familiar with the best practices of modern day frontend engineering.