They do degrade over time, especially due to weathering of the seals and UV exposure, but all the quoted numbers are worst-case.
(Inverters are more complicated products and may need more frequently replaced)
Was the electricity extremely expensive? Yes.
Reliable electricity has a certain worth. And that is vastly lower than what nuclear power needs when running at 100% 24/7 all year around.
And that is disregarding that EDF is already crying about renewables crater the earning potential of their existing nuclear fleet due to load following and increased maintenance costs. Let alone horrifyingly expensive new builds.
But we should of course keep our existing fleet around as long as it is safe, needed and economical. In that order.
EDF is already crying about renewables cratering the earning potential and increasing maintenance costs for the existing french nuclear fleet. Let alone the horrifyingly expensive new builds.
And that is France which has been actively shielding its inflexible aging nuclear fleet from renewable competition, and it still leaks in on pure economics.
EDF isnt crying. It's just treated poorly even by looking at ARENH tax which was replaced with another one this year, while ren business gets CFD's and curtailment payments.
French nuclear fleet is extremely flexible, RTE data is public. In fact, due to ARENH law EDF was forced to subsidize competition because otherwise that competition would not exist.
Also remember that large parts of a nuclear plant is replaced over its operational life. Control systems, steam generators, turbines, generators, tubing, valves etc.
What stays is the outer shell and pressure vessel. A nuclear plant doesn't just "work" for 60 years. And there's no trouble designing renewables with a 60 year lifespan.
We just don't do it because spending money on getting their expected operational lifetimes from decades to 60+ years is betting on extremely uncertain future returns.