I like how for the past 10 years, everybody has been espousing language/framework xyz as being superior for the reasons you've just said (asynchronous, responses per second, memory footprint etc), but as soon as you say Java does it all better, suddenly developer efficiency is most important.

FWIW, it always seems like a mostly zero sum game to me. Whatever efficiency you gain in using (e.g.) Python+Latest Frontend Framework+Backend Framework, you lose through having to wade through yet another set of new concepts and documents for those frameworks.