Was duolingo ever known for high educational quality? To me duolingo's main pitch was a way to gamify language learning. Of course it became a victim of its own success as soon as you could "pay to win".
I don't think so. I see its pitch as "the best kind of exercise is the one you do", maybe preferable to playing a game, but not an efficient way to learn. How useful it is to you will probably depend on how effective the sounds and streaks and home screen notification stuff is for keeping you motivated. Personally, I'm motivated by quick progress and outcomes (streaks don't do anything for me), so Anki is actually stickier, though I must be in the minority.
Because they focus so much on beginning learners for whom nuance isn't important, this change doesn't seem like it'll hurt them.
Being successful at Duolingo was always being like that guy who wins scrabble tournaments in French and Spanish without being able to converse in them. It's just a game and winning at it doesn't necessarily align with being functional in it. Otherwise second language schools would have long been extinct by now.
Far behind are the days when free version of Duolingo was playable. There are so many dark patterns these days to keep users coming back, gatekeeping something or otherwise to just push them to pay for the usage.
I don't think it was ever known for being high quality, it was known for being "accessible" and then they forgot about what their original goals were. They got pretty disappointing IMO when real languages were in need of updates for a long time (I don't know if the Chinese course ever got features like Stories) while they added a bunch of fictional languages.
Was duolingo ever known for high educational quality? To me duolingo's main pitch was a way to gamify language learning. Of course it became a victim of its own success as soon as you could "pay to win".