Nuclear generates a lot more kilowatt-hours per square-foot than renewables, especially in places that aren't very sunny or windy. I am not advocating for a 100% nuclear grid, but I don't see how we can get rid of coal without a decent number of nuclear plants.
It's very relevant, because a) we need to reserve enough area for people to live, and for growing the food we need, and hopefully for a few parks as well, and b) transmission and storage of electricity across long distances is not trivial. It isn't feasible to, for example, cover the entire surface area of Africa with solar panels and use that energy to power the rest of the world.
That entire thinking is flat out wrong - even if we were 100% solar the idea we won't have any land left to live on is insane [1]. Solar will get more efficient and more dense, to what peak we don't know but even at current efficiency we could more than power the world in unused and unlivable land.
