I remember when Steam curated their store and indie devs complained because Steam didn't select their games - Steam was basically a king maker. In response to those complaints, Valve introduced the Greenlight program and a bunch of asset flips and shovelware started getting the green light. So, Valve added a cost for publishing a game to slow down the volume of crap getting green lit. Since then, they have added the Discovery Queue, Steam Curators (which is useful for specific use cases, like finding couch co-op games or multiplayer games you can self-host), and Next Fest (which brought back demos) to help gamers find the games they want. So, it's not like Valve is ignoring the problem, provided that you think the problem is difficulty finding games you want to play.

Also, my remembrance is that after they opened the store up to more games, they discovered audiences for genres that they (Valve) were not aware had much of audience these days, like visual novels, hidden object games, and adventure games. So yeah, I think if the choice is between less curation with tools to find games or more curation with more indie games or entire genres potentially being overlooked, I prefer the first option.