SAT® question: Barrymore had many wives, Garrick one, but each is remembered...

[Ecoke0005]

Hello, I spent at least 3 hours tackling this sentence, yet still can't figure out the structure of it.

"Barrymore had many wives, Garrick one, but each is remembered not for his women but for his talent."

I don't understand how the comma between "Barrymore~, Garrick one" can connect two independent clauses. Isn't it a comma splice? I can see "had" is omitted between "Garrick" and "one", and "one" means "a wife."
But why not use "but or a semicolone" intead of the comma?

Please help me out...