I'd argue it succeeded (at least more recently) because of the UX that companies like Github and Gitlab gave, not particularly linus or because it was free.
Git succeeded because it was good. Github just made it more accessible.
This gets lots of people to look at it. But those people still have to decide in the end of the day whether it is actually useful for them.
Just because Steph Curry uses Under Armor doesn't mean everyone will too.
I think obviously something created by Linus was deemed to be of great value, but what made Git as profound as it is today is: UX for the majority of people who are beginners, which was Github backed by millions of other developers.