Earlier quoted context omitted.
It's because these things aren't priorities for management so they aren't for the engineers, the latest fads like AI are priorities and therefore they get integrated everywhere.
that's a copout in my opinion. Most of the quality decisions are established by team culture and experience. If a team is full of webdevs, no amount of management investment in performance will make a good app. conversely, a team of high performance members will be able to deliver quality apps despite management's input.
I mean take a look at what happened to Boeing, there were people that cared about quality down in the trenches but they were overridden by the people that didn't care about quality, just about shoving items out the door.