He's saying this because exclusives aren't working out for them or the people doing them. Exclusives are hated, not financially viable, not hurting Valve enough, increasing pirating and might actually be hurting the games enough to make securing future exclusives even more expensive. Indie exclusives at this point for Epic basically mean floating an entire studio.
This isn't Tim Sweeny saying to Valve, "Come at me bro."
This is Tim Sweeny being, "Please for the love of God let me fuck you over for this horrible, horrible decision I made."
There is no way this doesn't come off as weakness. Its a plea for help and for him to save face. Fuck off Sweeny, eat the bowl of shit you made.
A. Won't happen, would be nice if it did but sadly it won't ; B. Enjoy losing more money than you already did as both Ubisoft and Rockstar sell their shit on their stores while getting extra from you suckers.
There was a good point on Twitter that Steam lets you make infinite keys and doesn't take any cut. So if you wanted to sell your game on a website instead of Steam, you could do so. Or if you wanted a lower percentage, you could use a key reseller who takes less of a cut. So this is trying to hurt them through lowering their margins by making them stop this policy. Which they'll obviously never do.
Only issue though is that many pubs AAA like A/B, Bethesda, WB, etc are gonna go to Epic or Steam instead of GOG because they know damn well that CDPR will call them out if they try anything scummy with DRM
This is actually a problem as well. You don't need to buy Anno 1800 on Epic. You can just buy it off the Ubi launcher. Or the Bethesda store (Also Bethesda is not leaving Steam. They're bringing more games to it). Or the Rockstore err...store. The problem with exclusivity is that it isn't really exclusive. Most Triple A studios nowadays have their own launchers. Nearly everyone with Steam has Uplay, so they can skip Epic.
That's another problem Epic has with exclusives. People are just going around them.
Epic Exclusives will eventually stop. As usual, Steam doesn't have to do anything about it. Because they're so harmful to Epic its basically worth it for Steam to let them blow millions and millions on securing exclusives for more and more money, while pissing off the audience they need to convert and people go around their launcher to AAA ones. It also forces Epic to buy exclusives rather than work on making their store better.
In a way, Epic store fucked themselves into a corner with the exclusives. Because it resurrected the piracy problem, instantly made them hated, and cost them massive amounts of money. Its been a chain around their neck. You can't get around a major PC release now with people asking, "Will it be an Epic exclusive?" And that's not in a positive way. Its basically asking, "Will I be pirating this or not?"
\EDIT:
Also they'll never get any good Japanese game exclusives because it'll be a cold fucking day in hell before the Japs work with a majorly owned Chinese company.
Another thing I just realized, they'll try to blame Steam for exclusives because they didn't take Sweeny's shitty fucking deal. Hey Sweeny, I guess your consumers actually do decide who wins a war in CONSUMERISM, YOU DUMB GIGANTIC FAGGOT.