https://www.pcgamer.com/epic-will-continue-to-sign-exclusives-even-for-games-already-on-steam/

"We don't want to do that ever again," Epic Games Store boss Steve Allison said in March, in the wake of the uproar over Metro Exodus making a last-minute move from Steam to Epic. Then it did something very similar anyway with Anno 1800, although that game will remain available for pre-purchase on Steam until it launches—a fair compromise, I think, but a distinction that didn't make much of a difference in the eyes of unhappy gamers. 

Earlier this week on Twitter, Epic CEO Tim Sweeney clarified the company's position, saying that after some post-GDC discussion, it was decided that the final call is ultimately up to individual developers and publishers.