I think this is more than good enough to be the "straight answer" you're looking for all on its own (& it's definitely not a case of "it might" - it definitely will).
However, on top of the cost, there's three additional reasons:
2. It will take longer
3. It will need to be geographically distributed to an extent that will incur a significantly broader variety of local logistical red tape & hurdles
4. One of the largest components that will cost more is grid balancing energy storage, which is not only a cost & logistical difficulty, but also an ongoing research area needing significant r&d investment as well.
Given all those comparators, it's a testament to the taboo that's been built up around nuclear that we have in fact been pursuing your "all renewable" suggestion anyway.
Longer than nuclear? Where did you get that idea from?
Anyway, about #4, nuclear can't economically work in a grid with renewables without batteries. With renewables, you can always temporarily switch to a more expensive generator when they go out, but anything intermittent that competes with nuclear will bankrupt it.
When we're talking about societal public investment - even investment in the private sector - capital cost is a much more constrained consideration than anything related to abstract market "competitiveness". The latter does not influence the former in real terms (only in argumentative policy terms, which are unfortunately more impactful than they should be).
> Longer than nuclear? Where did you get that idea from?
Longer than nuclear to do what? I was replying to the above commenter who said the following:
> in theory any amount of power a nuclear plant would generate could also be achieved with large amounts of renewables
TTL for individual nuclear is obviously always much longer than for renewables but time to any arbitrary large generation goal is almost certainly shorter for nuclear (barring taboo).