It already is taxed as ordinary income - RSUs are taxed as cash when vested. Incentive stock options (you have to buy these out at strike price) are taxed as in

It already is taxed as ordinary income - RSUs are taxed as cash when vested. Incentive stock options (you have to buy these out at strike price) are taxed as income for value at exercise less strike price. The advantage of RSU over regular cash comp is that they can appreciate while not yet vested - it’s like putting your future salary into stock market, it can go up or down. Then when vested, it’s taxed as cash salary (no long term capital gains advantage here).