Amazon doesn't have a majority shareholder. Most of these huge companies don't. Gates doesn't own a majority of Microsoft, Page and Brin even together don't own a majority of Google, etc. These companies are owned by everybody's retirement fund.

It's actually becoming rather a problem because you have these gigantic containers of wealth but there is no one captaining the ship who can do anything bold with it, because that requires shareholder approval but the underlying shareholders don't even know what companies they own much less have any idea what comes up for a vote. Meanwhile the fund managers are the most conservative people imaginable and are far more interested in stable returns than making the world a better place, so the entities that have the resources for moonshots don't have the stones to actually attempt them.