Epic Games only had about 2,000 in 2020 and they also develop games, store front (although really slowly), so it's at least a 4x more than they need.

But also their previous monetization seems to try charge per professional developer which is a limited audience compared to consumers, especially if you want to maintain a AAA engine (which they weren't at yet) given it seems fast pace techniques & improvements. Maybe by selling cloud servers for networking, which I think maybe they were too expensive compared to alternatives.