Let's not act like Steam didn't prerty much own the PC market. The Epic Store getting Exclusivity is a drastic way to be on the map. Otherwise how would they challenged Steam who has all the games and gamers ?
Maybe by providing competitive consumer friendly features, rather than either doing worse/barely on par than Steam in every respect on its consumer friendly features? If Epic actually put in the effort rather than buying their way in people would be happy. As is the Epic Store is worse for consumers, has less features, has less accessibility options (Steam's Controller API is important for handicapped people to play games comfortably), and gives consumers
less options to buy their games from.
They could start challenging Steam by trying to make their client competitive. If they weren't capable of doing anything close to that right out of the gate then they should have waited to launch their Store/Updated Client until they were capable of it right away.
Imagine your argument from a real world perspective, a new store called V-Mart is created by a billionaire and is trying to compete with Wal-Mart. How do they do it? They could offer better warranties/a much better refund policy, lower prices on products also at Wal-Mart, special programs like spend X$ get Y$ off, etc, or they could take the lazy way out and offer none of that and instead pay companies to sell their products exclusively at V-Mart and not Wal-Mart. Imagine if you could only get [your favorite food/drink product here] at V-Mart and Wal-Mart/your store of choice could no longer carry it, so you're forced to go to V-Mart even though V-Mart is worse/barely on par than Wal-Mart in every conceivable way other than having your product of choice. (and tbh this analogy works really well, no one gets upset when Costco has their own "1st party exclusive products" in the Kirkland brand, just like no one gets upset that Epic/EA hosts their games on their own stores. But when you bring in 3rd party products, it gets stupid.)
Like, it's really weird how something like GOG has all escaped this seething hatred that Epic is receiving, and it's because they are not paying 3rd party games to go to them exclusively. Hell, GOG actively turns away games that are on Steam with their curation.
e: FWIW I'm not a Steam fanboy - I actively use Origin & GOG Galaxy and buy from both, and tbh I also use Epic to play Fortnite exclusively, but I'm not going to buy anything from Epic's store until they're willing to be competitive in a consumer friendly manner. There's always a better path than 3rd party exclusive buying, they just have to be willing to put in the work. Origin has better support response than Steam and the nice EA subscription pass plans and I like it for that, and GOG does a lot of work in going the extra mile on each game on there to make sure they work well and have goodies for their consumers. Epic offers literally nothing over Steam right now.