Google Play is allowing Epic to do it. Fortnite is still on the Google Play store.
(The writing has been on the wall and Google is already adapting - they sent out surveys last month to some developers about dropping the 30% fee and charging developers an annual listing fee instead - possibly also fees for bandwidth/storage used like a hosting company does. The survey also mentioned plans to spin off the Google Play store as a separate non-Google company.)
Aha, saw that myself an hour ago too. Wish I'd downloaded Fortnite now when I could. Thanks for the correction.
The Google survey I received specifically asked about experiences as a developer with the Epic Store, whether I thought customers would pay a subscription fee for access to the Play Store & Android updates, and whether I would trust the Play Store & Android if they were no longer owned and run by Google/Alphabet. So it will be fascinating to see how the court rulings change the tech landscape.