Like every PvE game which does not have hundreds of people working to churn out content, its playerbase will dwindle until only those who do not get bored by its gameplay stick around. Whether it's Left 4 Dead, Payday, Deep Rock Galactic or Vermintide, those types of games follow this pattern...
And I for one, see no fucking issue with that. It's a great game, people play it until they have had their fill and then move on. Helldivers 2 is only an outlier because of how hard it hit at launch. It absolutely does not have the content pipeline to keep a large playerbase engaged, so yeah it will not keep printing a lot of money, just a little bit every now and then.
Now excuse me as I go and spread some managed democracy.
The Epic Games Launcher is so far behind on features compared to Steam it's not even funny. Epic chose not to try and compete with Steam on that front and to try and force users onto the platform with exclusivity deals and sweeten the deal with free games.
The one user-centric killer feature Epic has in their stack IMHO is the built-in multiplayer crossplay. Except it's not even exclusive to their store ironically (you do need an Epic account for it though).