Valve pushed through and, over the years, turned a completely miserable experience into what Steam eventually became...and then they grew, and grew and grew and fundamentally changed from a heavily curated storefront to a almost completely unsupervised collection of thousands and thousands of games with almost zero discoverability
This is factually wrong. The Switch store is an example of a store with zero discoverability because it offers you almost zero tools to find interesting games, aside from a unfiltered "New Releases" list and a top seller list.
You know what else is a store with zero discoverability tools, not even a wishlist or a search feature? You're correct, Epic store.
Steam offers you discoverability tools and multiple ways and filters to personalize your storefront. And even if you completely ignore these tools I guarantee you will never see the hundreds of trash games hitting the store every month unless you specifically seek them out.
All these asset-swap games everybody complains about because Jim Sterling made a video about them literally don't matter at all for your store experience.
that developers grew more and more unsatisfied with.
Do we actually know which developers are currently unsatisfied with Steam? I would assume smaller ones that don't get noticed in todays oversaturated indie games market.
Epic store won't improve the situation at all for these devs as Epic is - at the time - only interested in giving high profile indie darlings and AAA games a spotlight.