The problem is that it's explicitly not real income for those working at companies which aren't publicly traded. For publicly traded companies, you typically se

The problem is that it's explicitly not real income for those working at companies which aren't publicly traded. For publicly traded companies, you typically sell-to-cover at vesting time, so you're already doing this sort of thing usually. For private companies, that's not an option, so you would have to pay tax at vesting time for options you could quite possibly never have an opportunity to sell.