At the same time, Java’s threads are so easy to use — without of the portability or debuggability issues of native threads — that threads don’t seem that bad to Java programmers. Yeah, shared state can be a foot gun, but so can global variables. You just keep things as pure and easy to reason about as possible. And Java has had concurrency primitives that keep you from having to deal directly with threads and locks for over a decade.
I don’t think “events” and threads solve the same problem. If your program would work just as well doing all its work in a single thread then yeah, you don’t really need threads. If we’re comparing “events and callbacks” async style to async/await style where you write your code as if it were running in a thread (even if it isn’t), I think the latter wins.