As are most of these "laws". The idea isn't to do a conclusive, thorough examination of all things under the sun and render a statement that reflects that particular moment in time. The idea is to make an observation--perhaps true, perhaps false--that helps us maintain a healthy mindset when examining and comprehending things. It's not meant to be insightful, it's meant to encourage us to strive for better insight.

It sounds like a manifestation of the pareto principle. I would in no way be surprised to see scientific advancement follow a power law distribution among contributors where the top 5-10% produce more and better science than the bottom 90% combined.

There's all kinds of reasons to expect that too... Everything from funding, likely collaboration partners, talent, etc.

That would give it some theoretical basis.

It's purely rhetorical but - the specific 90% figure aside - it's fairly straightforward that not everyone can be the best. Everything else is just figuring out what sort of distribution you have.

In many fields the definition of "crap" depends, after all, on what the rest of the field's output looks like.

90% of published laws are BS.

It’s not quite the Liar’s Paradox, I think Sturgeon’s fits into the other 10%.

Seems like an empirical approach to addressing this would be more effective. Otherwise it's just a gut feeling. I am not saying its wrong its just lacking in verifiable information.

90% of Sturgeon's Law is crap.