Or, worst case and highly more likely scenario in the grander scheme of things, not only Valve but ALSO other megacorps decides to go down the Epic Route™; signing a one-year exclusivity deal with devs to publish the games on their store. Better yet, every single developers out there decided to just fuck paying a % cut to stores and launch their own launcher.
Now the question is, what does this all matters for the consumers? If there's actually nothing in it for the consumers, why should they care? What, with lower cut means devs gets more money to fund future projects and that automatically translate to more good games coming out? Please.
Also, as far as I know, Steam's exclusives are games made by Steam, so they've got all the rights to keep their own games exclusives to the stores they established. Or I guess you can say it's the lesser evil. Significantly, much lesser evil.