France is now on ancient fully depreciated nuclear reactors that are soon in dire need of replacement. Of course it’s cheap. But they have huge investments ahead of them to replace, upgrade, refurbish, etc. They have identified that that need to expand renewable energy to 50% of power generation, at least.

We’ve also seen recently that Germany has had to save France during hot summers when their reactors have had to shut down.

What’s the lesson from France? Build lots of nuclear all at once many decades ago when labor was cheap and then stop investing and letting your infrastructure rot, and you’ll have cheap power for some limited time? Is that something anyone can or should copy today? No.

Now, even VALCOE (value-adjusted LCOE) of wind and solar is coming down well below all other fossil and nuclear alternatives. So how can you say betting on renewables was the wrong at this time? It has been expensive to transition but long term it’s drastically cheaper than everything else. And we haven’t even started getting the benefits of how repowering old renewable power plants is significantly cheaper than building new ones.

Simply not stopping the most modern nuclear plants we had (like Isar 2 in Munich) would have made a nice impact on costs and CO2 emissions.

Building new (nuclear) ones is probably not worth it, though.

The implication you're trying to draw there is a non sequitur. That situation doesn't contradict what I said. Moreover, France is going to be dragged kicking and screaming into the renewable age because they can't afford to subsidize nuclear builds enough to make a nuclear approach work.