I'm convinced designers have since long overthrown human-machine interaction experts, and usability consistently went down in the search for what's visually appealing and cleaner. I particularly blame Apple as a trend-setter in this, along with everyone that dumbly followed the fashion. No appeal to authority will ever convince me that disappearing scroll indicators are good for me, as I've been burned by them and I see less able people around me having ever increasing difficulty navigating modern interfaces thanks to similar innovations.

The "professional experts" are not interested in usability. They care only about sales and/or engagement. You can see this in every consumer product, not just software.