There is 100% nothing stopping the Federal government from offering a full-faith-and-credit-backed "America electronic transaction system" for electronic transactions, with those fees handled by taxes.
But much as there's nothing stopping the Federal government from greatly simplifying the burden and toil of tax season by issuing 90% of Americans a pre-filled-out "This is what you owe; sign this and return it or dispute it with your own filing," we won't do that because fully half of Congress is from a party that has, as a plank, that private institutions serve the public interest better than public institutions.
But much as there's nothing stopping the Federal government from greatly simplifying the burden and toil of tax season by issuing 90% of Americans a pre-filled-out "This is what you owe; sign this and return it or dispute it with your own filing," we won't do that because fully half of Congress is from a party that has, as a plank, that private institutions serve the public interest better than public institutions.