Of course not, the IRS takes cash. It's far simpler that way, and probably will remain that way for quite awhile.

And it probably should - the IRS is in the business of collecting money from citizens and corporations. It should not be in the business of managing investments and RSUs in thousands of private entities.

Yes, typically there is withholding to help cover the taxes, but for four year grants in the range of $1m+, the default withholding doesn't fully cover the taxes.

Are you joking? No. They don't take beaver pelts or glass beads either :)

Fair and equitable are not often words used to describe the US tax code.

But if I pay you bitcoin for goods/services, you still need to pay tax on that, in USD.