Just FYI this story originally was about photography as clarified by the author at https://jamesclear.com/repetitions

In photography, you can get lucky. When I come back from holidays and review a thousand of random snapshots, a couple of them look great. Take 200 shots of a single thing, and one of them might be pro-level due to pure chance. Yet I'm not sure how well this "randomly great" percentage would translate to me playing the violin, dancing ballet, or writing a song.

I am not a musician but my guess is that they don't sit down and say "I'm going to record an album with 9 bad songs and one good one."

They do their best on every song and that's just how it turns out.

It definitely works for the "writing a song" bit.

A lot of things can be said and some expressions of the same thing are just better...

After hearing this story for years and finally trying to source it, as far as I can tell it's not entirely clear this experiment was ever actually run -- and in fact is sourced in the link behind your link as a "parable."

I can imagine it's true that churning out quantity is its own education but I can also imagine there's a plateau past which deliberate practice and polish matter quite a bit.

Well t's a better parable than the one about boiling a frog, so I guess it got that at least.