It's a bit of a side-step of the question, but there's no reason we need to domesticate solitary cats if all our dogs and wolves are dead. There are plenty of social cats who could be bent to our will.
Lions are one option, but probably a bad one as they're so big. I'd posit that hyenas are the next best option. They're highly social endurance-predating feliforms and fill very similar niches to wolves in their environments.
They're even already well on their way to domestication in places like Harar.
