It's a gain based on your invested capital, isn't it? It's textbook capital gains. PoS, PoW, whatever.

Mining is reportable as ordinary income in the US.

Cryptocurrency earners have to report ordinary income taxes as well as capital gain/loss taxes.

Its not that hard, less than ideal, its also easy to immediately convert to USDC or fiat automatically, or find other deductions to reduce or eliminate the tax burden.

A baker buys an oven which they use to bake bread. They sell the bread for dollars. Is that capital gains?

Odd that you call it textbook capital gains, what textbook are you working from?

It seems pretty clearly like income to me.

No, mining is in no way capital gains. Capital gains is asset price increase.

Under that definition, almost all income would be considered capital gains.