Comment by leptons

I guess I wasn't a "mainstream" developer in the 1990's? Before XMLHTTPRequest, I was using iframes to asynchronously load content into the browser, essentially accomplishing the same thing before "AJAX" was a thing. We were doing long-polling before there was websockets. I was using Javascript and CSS to create "DHTML" SPAs before XMLHTTPRequest, with Javascript for front-end and back-end. You either know the potential of the tools that are available, or you don't.

But I guess my anecdotal experience doesn't matter, because I wasn't a "mainstream" developer? From my point of view, everyone else was missing out on using one language for front-end and back-end.

Context switching has a real cost in terms of developer burnout, and it's something I've happily avoided for 25 years.