They could. But they get ~25% of their revenue from the EU, so they'd have to give that up. They'd have to risk losing their social network monopoly, and risk a

They could. But they get ~25% of their revenue from the EU, so they'd have to give that up. They'd have to risk losing their social network monopoly, and risk an upstart getting millions of users (in the EU) and then posing a serious risk to Facebook globally.