If they reproduced tube amps they might make a go of it but I'm betting anything newer will be cheaper from China fully assembled. On of the big attractions of the old kits was saving money.
I agree that they couldn't compete with China, not by a long shot. Personally, I hope they don't try. I believe there is a market for decent quality kits and people wouldn't mind paying for it. I doubt it's a market that will make billions, but I do believe there is enough to support a small group comfortably.
The big question to me is, what type of kits? Test gear such as power supplies, function generators etc, would be a given as those would have appeal to anyone involved in electronics. Since test gear doesn't have to be tiny thru hole kits would work great. But then what? Beats me.
SMD isn't kit friendly, even less so for beginners. But who wants a gizmo for their micro assembled with thru hole components? Micros are today's version of Ham radio. They're everywhere in our lives doing their magic so a large portion of electronic hobbyist gravitate to them, just as prior generations did to radio and their rf voodoo.
There just doesn't seem to be many places for thru hole kits but kits are no place for SMD.