The appeal of something like PHP these days is not that it has any particularly unique features, but that it is ubiquitous, has withstood the test of time (meaning it's relatively bug-free), is well supported (meaning it won't disappear any time soon), and is relatively easy to find developers for. Those features alone make it a contender for projects that don't need a specialized language.

I don't buy that. You can't have it both ways. You can't discount PHP4/5 criticism because PHP7+ is good and then in the same breath hold PHP above other tech stacks for passing the test of time, not when PHP7 is younger than Rails, Django, and React (and even Vue). Those frameworks have passed the test of time more than PHP7+.