For low income+equity Americans, are the benefits of gains harvesting worth the early withdrawal penalty of a 401k?

First of all, this assumes you've already fully contributed to your Roth IRA, because no capital gains tax on that.

When you withdraw from your 401k, you pay the final amount. If you withdraw early you also pay a 10% penalty.

If you're making $20/hr you've got about $6750 in income left for which you wouldn't pay any federal long term capital gains tax. Meaning you could sell and rebuy the same year+ old position to realize those gains and raise your cost basis on up to $67500 in assets by 10% without paying any income tax. Mind that, 10% of 90% is 9% of the original amount, but as long as your regular earnings are under $48,350 you can still perform *some* loss harvesting each year.

To me, it seems for low income investors in their 20s, gains harvesting is totally worth the penalty for early 401k withdraw.

Am I missing something?