Well sort of. Reliable base load power (nuclear, coal, gas, hydroelectric) has become essential to modern civilization in a way that transcends economics. If we can't keep the lights on then nothing else matters. Thus, competent governments will find ways to keep those plants running regardless of cost or environmental impacts. Those that don't will end up as failed states like what is happening to South Africa right now.

It's cost-efficient to operate in profitable scenarios and halt in costly scenarios.

Optimizing profitability concerns the full operating range, not same anecdotal outliers.

All energy-intensive industry operates only when circumstances are favorable. Sometimes it's more profitable to reduce output temporarily, e.g. during high gas-prices, or during weekends when workers are more expensive.