A couple of things here:
1) I think Alan Wake 2 being exclusive to EGS played a strong part of this increase. Especially since they funded the game to begin with.

2) Tim Sweeney whines about competition and fairness yet, he keeps stealing games from steam and making exclusive to EGS. (Rocket league, fall guys, Alan Wake 2). Man, I HATE exclusives. It's not competition, it's desperation. The guy is a hypocrite. Competition, for the consumer, is having those games on BOTH stores and having a price war.

Now despite me having over 4000 games on steam, I've always said, of anyone can make a game store as good or as useful as steam out better, I'd be happy to purchase my games there. The biggest trouble with EGS is the fact it is just a store. There's no community, workshop, competent voice chat, game recording, etc.

As long as EGS remains the petulant Little featureless game store, why is it worth my time?

I read in an interview with the store boss, they have great plans to take on steam. They plan to optimise the software so it is faster and lighter on resources. They still don't get it. It can be as fast as you like but still, why would I switch to buying games there?