You haven't mentioned why you think Git won. If by "won", you mean "is more popular", then yes, it won. But that criteria alone doesn't make a decision bad. When changing gives you no clear advantage, why change to something more popular?

Isn't that akin to arguing that choosing to distribute your movies only on Betamax is not a bad decision?

won what?

It has won GitHub, that's mostly it.

Separately, GitHub has won the "place where you share you project code" prize that used to belong to sourceforge.