It does seem a lot simpler to plop down a bunch of concrete in roughly the same area as today's fossil fuel plants take, compared to rewiring and repurposing a third of a country to get enough solar panels and wind turbines in place (the latter while keeping residence distance requirements in mind). Not sure if that is factored into the feasibility when people talk about how expensive it is.

I agree that it doesn't make economic sense in an ideal world with twice as much space per capita and/or a lot more time to find and purchase ideal nooks and crannies and wire them up, but that would require moving to planet B. Note I'm not talking about nearly-empty USA, Australia, northern Africa, etc. here; rather, take 2-3 random European countries (highest emissions per capita after north america, so you know, the place that needs to get change happening) and you're very unlikely to hit only ones where not most/all of the land already is already allocated to some purpose.

I also agree it's likely already too late to get started on new nuclear plants, like, it's nearly so late that we might as well just go solar and wind for the rest of the way. But I don't think it's quite at that point yet, considering for example that regions in southern germany with big-ish distance requirements for wind turbines are placing nearly none (and germany is not even one of the countries that I would count among those that are out of space), it's apparently that full already and they've got like 80% of the way to go in phasing out fossil fuels.

Honestly the main hope I have these days is solar panels on crop fields becoming a real thing. That would grant a level of scale (and somewhat protects from crop failure causes like hail and drought) that would make me see this energy transition as feasible without nuclear (pushing the recycling problem onto the next generation, but better to deal with a billion worn panels than a billion displaced people (both figures are figurative)), but so far there's little adoption.