That's the levelized cost of energy (LCOE) that the article speaks of: https://en.wikipedia.org/wiki/Levelized_cost_of_energy

It's a well understood way to evaluate cost. In short nuclear is at the very high end of the spectrum and not really dropping because (so far) of a lack of a learning effect.

Solar is on the very low end of the spectrum, as the article points out. And wind is somewhere in between. Both of those are still dropping dramatically because of learning effects. E.g. with offshore wind, bigger turbines mean more surface area and more load. There are some 20 MW models now coming online. These things are gigantic and obviously a bit capital intensive. But they also produce a large amount of power very reliably. And compared to nuclear which has gigantic capital cost, it's actually very good. And there are still plenty of ways left to find further cost reductions.

Baseload is a poorly defined notion often wielded in hand wavy style to argue that nuclear is needed. This overlooks a few important things.

1) nuclear is expensive for that too and cheaper technologies exist with learning effects of their own. Batteries were mentioned in the article for example. Another one is cables. Cables allow different regions to import and export electricity to each other. That provides base load and the average peaks and dips in supply and demand over large areas are far less dramatic than they are locally.

2) intermittency is not actually random but predictable and typically local. So are demand cycles. Weather forecasts allow grid operators to plan weeks/months in advance; mostly intermittency does not come as a surprise. Hot weather means everybody puts on their AC, high solar output, relatively little wind. That happens every year in roughly the same months. Of course air heats up and you get a lot of airflow to other areas, which will have lots of wind as a result. Weather predictions are mainly about figuring out where the low and high pressure areas are and how they move around.

3) base-load is a relatively poorly understood notion. How much for how long do we need? And how much extra would that be? Those would be reasonable questions to ask (and answer) if you are a grid operator. People assume a lot of answers to these questions that are probably false/irrational. The real answers are far less dramatic.

4) Some countries already have very high proportions of renewables on their grid. So far without causing issues. Better still, some countries with historically very unreliable grids (e.g. in the middle east), rely increasingly on renewables to fix that. That suggests, renewables actually improve resilience if you don't have enough base load.

So, it's not all that black and white. The answer isn't blindly putting your trust in nuclear to get some really expensive base load that you don't actually need. But sitting down and doing the math. A lot of people seem to be coming up with outcomes where renewables are cheap, feasible, and plenty reliable especially when you use cables and batteries as well. The sun always shines somewhere and wind is always blowing somewhere. If you simply connect those places with cables, there's not a whole lot of base load that you would need beyond that. If any at all.