This caught my eye when a nuclear plant in Iowa (near friends, including one who retired from working there) got slated for shutdown, over a decade before end-of-life. They'd lost a key industrial customer that consumed 30% of the plant's output to much cheaper wind/gas. At that point, operating costs went into the red. The plant was no longer generating the revenue to pay off its own debt. It was a purely economic decision.
And yes, the wind and gas that ate its lunch are also capital expenditures, amortized over time. But they're still much cheaper.