These are of course not hypothetical fantasy projects that may or may not happen but actual panels on the ground or spinning wind turbines delivering lots of power to grids today.
It's well proven technology. Clean, cheap, predictable in performance and installation cost, etc. Sort of the opposite of nuclear where every new plant is a bespoke thing that is all but guaranteed to blow through it's time and cost budgets. We can speculate on why that is but the fact is that there just isn't a whole lot of nuclear capacity coming online. Which is perhaps part of the reason why it is proving so expensive and hard to build more of it. You might even say it has perpetual issues proving, or rather disproving, it's viability in recent decades.
Whatever the reason, renewables are now dominant in newly installed capacity. These don't need more viability studies. That happened years ago. Renewables are now well on their way to being the dominant source of energy in a lot of markets. In some markets it already is. 10% would be a a distinctly unambitious goal. 50% is a more ambitious goal that could be reached in a decade or so. This decade possibly. With nuclear, that amount of contribution is unthinkable. The cost would be astronomical and there are no concrete plans to make that happen. The budgets for that don't exist. All we have is a lot of magical and wishful thinking.
Also, base load is a very loosely defined notion that somehow never gets nailed down to actual GW of capacity or GWH of storage needed. Can you be specific? The reality is that the only western nation plagued by rolling blackouts is the US, which has a lot of aging nuclear plants and is a bit behind on investments in infrastructure. In places with a much higher dependence on renewables, more modern infrastructure, and less nuclear (like essentially most of Northern Europe) blackouts are basically not a thing.
And of course nuclear sometimes goes offline for maintenance and that can take up significant amounts of time. When it does, it's gone for months or longer.. France is a good recent example that had a large portion of their reactors offline for maintenance just when there was a big energy crisis on courtesy of Russia. Where did their base load come from? Imported energy. France was a net electricity importer during 2022 because of this. 16wth or so. Only about 4% of it's needs; but still. They managed fine. The European grid has a lot of resilience. What grew massively during this period? Renewable energy production.
