It's an interesting idea, but for my money people haven't explored the limits of what's possible on zero carb yet.
An inuit whale hunt, for example, in canoes. I think that would require a good level of endurance.
I think it takes time to adapt to zero carb. Lex has reported changes after 18 months. Every bit of endurance you want to gain you probably have to fight for.
When I was in a high altitude country, first I had low energy in everyday life then that lifted. Then I started running and couldn't handle much, but I was motivated and fought my way up to 7 miles, and could have carried on. I feel it would be the same with zero carb for some people anyway.
At the end of the day, maybe you couldn't reach the same feats of endurance as with carbs, but you could get a good level. We don't know what endurance we're 'supposed' to have by evolution - persistence hunting might be a late stage hunter gatherer thing, not paleo.