I don't think it's productive to talk about tax. Our economy should be designed in a way that workers capture a good proportion of their work. The problem at the moment is that when there are successful companies, a handful of investors and senior management capture practically all the gains. Amazon is an incredible company, and it's even more incredible that practically no one working at Amazon benefits from that.
Just letting that system persist and then hamfistedly grabbing the gains at the end and redistributing them is difficult for a huge number of reasons including both fairness and regulatory capture.