> The most prolific writers are journalists

You state this as fact without providing a dataset to back it. I think this is not true at all.

> most of the most successful people on the planet write little or nothing

It depends on how you define "success".

I would consider people like Linus and Dwayne Richard Hipp and TBL to be among the most successful people on the planet, and they write quite a lot.

Do you call people who capture then give away a billion dollars the most successful? I don't. To me the most successful are the ones who create billions in wealth and capture just a tiny fraction--enough to support their family and friends and live a good life.