I'd argue that PHP7 is the closest thing PHP has had to a quality revolution. It fixed a zillion things, got rid of some footguns like legacy mysql, and in general behaved a lot more rationally.

If you were doing things right, by that point you were already using Laravel or Symphony or something, so the change didn't seem as revolutionary as it was, but that was the moment a lot of dumb string concatenated query code (for example) no longer worked out of the box.