> It's been a long time since "quality" and "success" have been decoupled.

I think so, too.

I guess quality was a property of interest in the old days, because the path e.g. for commercial music was: Maximize profit -> Maximize sales -> Maximize what the target audience likes -> Maximize quality.

For TikTok etc. they bypass the market sales stuff and replace it by an 'algorithm', that optimizes for retention, which is tightly coupled to ad revenue. I imagine the algorithm as a function of many arguments.

Just relying on quality is an inefficient approximation in contrast to that.