My wife quit Duolingo the week before this announcement after years of watching Duolingo prioritize attention manipulation over learning. She had a nearly 6-year streak and was on the paid version at the time, but realized that it wasn't actually helping her learn any more: she'd at some point begun maintaining a streak just for the sake of maintaining a streak. The best documentation for Duolingo's decline is this a…
Duolingo is really only useful at the A1/A2 levels anyway. Once you reach B1, you're pretty much past the point where the vocab and grammar basics from Duolingo is useful and you need to move on to other activities (watching TV in your target language, having conversations with native speakers, reading books in your target language, etc).
Unfortunately as they got popular automated translation services got good enough that nobody was going to pay for a slightly better and slower translation enmass.
Once that happened, that's when it seemed like they dumped their goals of teaching language and instead focused on dark pattern money extraction.