Why does it suck for players?
Its simple and down to the way the platforms do their competition. Steam competes with other platforms by adding features and building a community and trying to attract a player base. It does this with its forums, elaborate chat and streaming system, built in guides, mods, etc. Steam is not just a store for games but a social platform and it is popular because of this reason. In short, steam is popular because players like using steam. Competing with steam would entail a new platform trying to compete with features that make players like it more than steam. This would cause steam to need to respond with new features to try and retain its players.
This sort of competition is good for players, because it results in a better player experience.
Epic on the other hand does not compete for players, it competes for games through exclusivity deals. It forces players who want to play the games it secures to use its platform, which due to its method of competition being the above, does not have features players enjoy on steam, or things like that, or novel alternatives. Its just a bad platform whose only asset is the exclusivity deals.
If steam were to compete with epic in this way, steam would need to spend money on exclusivity deals, which means less money spent on developing and maintaining the kinds of features that attract players to steam in the first place. This kind of competition in the long run actively harms the experience of video games overall, for all games and all players everywhere.
Epic claims its too hard to compete with this. They basically say steam is a monopoly because 'its too hard to make a competing product'. They argue that the only way they can compete is by buying exclusivity rights... which is a literal monopoly on the game. They are saying steam is bad for making a nice platform players want to use and they are being righteous for buying temporary monopoly. Steam does not have exclusivity deals. Games that are only available on steam are this way only because the developers/publishers dont want to sell them anywhere else, steam does not prevent them from doing so, it does not hold their game hostage. Im fine with using a games standalone launcher. In fact i slightly prefer it. But if its on a platform it better be on steam.