I've been involved enough with a few (mobile and PC) efforts in this direction, and now believe the US business culture can't create new ones in established markets.
The reason is the highly successful competitor, in that case Steam, inspires a sort of megalomania in those aiming to compete with them, which leads to spectacular self destruction and consumer confusion as stores try to act big long before they are self sustaining.
Also really makes me question your average USA based developer. Making a program and storefront to manage few dozen to few hundred applications can not be that complicated problem. I am not here even talking about scale of Steam libraries that outlier customers have.
There must be some fundamental problem with either developers or management system or both...
my completely uninformed speculation is that they didn't want to just build a clean, simple store that got out of your way, they wanted to throw in some sort of rent extraction or user control at every step.
It's the same issue as games. No one ever says "I bought this game becsuse of its clean UI". Not unless you're a dev doing market studies. But at the same time, a bad UI in many genres can sink a game. So UIs tend to be as minimal as necessary to ship. Even Steam had the same UI for some 15+ years beffoe finally giving it different library views
The minimal here was to take the Unreal Launcher (which was always meh. But devs rarely interact with the launcher) and shove the tab into there. Any problems with that launcher were passed to the EGS, and amplified by being B2C.
If I have to be honest, it's also tribalism. Exclusives are not a new concept even on PC. But the reaction to some EGS exclusives was so extreme. The PR hit didn't do many favors.
The reason is the highly successful competitor, in that case Steam, inspires a sort of megalomania in those aiming to compete with them, which leads to spectacular self destruction and consumer confusion as stores try to act big long before they are self sustaining.