A major part of it is that nuclear hasn't been allowed to be cheap.

There's been active sabotage from the oil industry since the beginning, starting with the Rockefeller Foundation sponsoring fraudulent science via their employee, Herman Mueller. To the CEO of Atlantic oil funding the creation of an explicitly anti-nuclear environmentalist group called Friends Of The Earth in 1970 or so.

Which coincidentally was about the time that the Rockefeller Foundation started funneling money to another explicitly anti-nuclear environmentalist group called Greenpeace.

The political pressure from these groups, plus direct pressure from the oil companies, got extremely restrictive regulations passed, with the goal, and result, of making nuclear more expensive to build and operate.

Look up the double guillotine break, which is a nonsense requirement that nuclear engineers have to design around. Nonsense because the equipment required to prevent this impossible scenario make it harder to deal with the actual likely scenario, which is leak before break.