Nothing against Epic, but they have a strategic incentive to encourage people to use their store. Getting a discount to use the engine in exchange for a store “exclusive” is a cost that I see developers not really appreciating. There is no free lunch.
I don't think that's unusual. When Valve announced Source 2 for free, there was a similar discount to use the engine: the game must release on Steam. Maybe that has changed in the 8 years of no news about the release of Source 2 for developer though.
