Base load plus peak load is just one way to run electricity production. There is also load following for instance.
Germany replaced nuclear with renewables while also reducing both coal and fossil fuel use in general: https://commons.m.wikimedia.org/wiki/File:Energiemix_Deutsch...
From the OP: >I'm sure the old ones would be replaced.
I think their point is that the old ones are still in use (sometimes extending their life rather than replacing them with better designs) because new ones aren't allowed to be built.
It's like banning new ICE designs and then complaining about how ICE aren't more efficient.
The answer unfortunately is no, the fear mongering largely won out.
And you also seem to have forgotten the thread your in with your last statement.
If it was actually possible to build a new nuclear power plant I'm sure the old ones would be replaced. If it wasn't for chernobyl plus three mile island (which released a comically low amount of radiation) maybe the west would have completed its conversion to nuclear instead of essentially pausing all construction for 30 years. But right now the options are essentially shut it down and replace with fossil fuels (wind and solar are not great providers of base loads for obvious reasons) or extend the license.