I've had this same cancellation conversation many times with JS programmers. I think it's fair to say there's a need for standardization. Evidence for this need is network request management is really poor in pretty much all JS apps.
Regarding other cases, there are already ways of handling those. I don't think just because many ask about something, doesn't mean it's not currently working.
controller = new AbortController();
const signal = controller.signal;
fetch("http://example.com", { signal: signal })
// abort request
controller.abort();