>but not paying taxes on capital gains
...that haven't been realized yet. As you draw on your reserves, you'll be forced to realize those gains and pay taxes on them, making this a non-issue.
>willingly "unemployed" in your productive years to "enjoy life" and "freedom"
Ah yes, because the goal of life isn't to enjoy it, it's to be as productive as possible! Freedom is overrated anyways!
>as the crypto miners trying to avoid taxes.
Are miners known to be tax dodgers or something?
>but if everyone just retired early or sat at home mining coins, where will society end up?
"retired early": there would be an imbalance of labor demand compared to supply. This will cause prices to go up, which will make it less attractive to stay "retired" and more attractive to start working again.
"sat at home mining": same thing that would happen if everyone decided to gold mine. eventually there would be a saturation of miners and it won't be profitable anymore, causing people to exit.