Hades was one of the first games announced for the Epic Games Store, before the PC platform wars had really started. Developed by Supergiant Games (of Bastion fame), the art style was on point and the Diablo-like gameplay swayed a lot of people, but a lot of folks just don't want to download the Epic Games Store launcher. That changes later this year.
According to a newly updated Steam page, Hades will be arriving on the platform on December 10. That's nearly a year of exclusivity, but thankfully it was a weird deal in that it took place entirely during an Early Access period. Once the final game is out, everyone can enjoy it together. The final game, mind, is still slated for the third/fourth quarter of 2020.
Hey, maybe the Epic Games Store will have a shopping cart by then (that never gets old).