Not too much new info here.
It's been interesting to me to watch this "fight" from a user perspective. I say fight in scare quotes because it seems to mostly be EGS whinging and splashing about and Steam just ignoring their existence entirely.
But it's interesting to me because I've always felt like Steam's moat was weird. I mean, it's PC. There's no moat in the same way that Android or iOS have. Prior to steam, people just put their items on their dang desktops, for crying out loud. Still can. Still do, for most software that's not games. And there's obviously ~0 cost to installing multiple launchers. It's what, a few bits of disk space (nothing compared to the size of even a small indie game, which will easily be 1GB nowadays) and an icon in your app tray, if you even let it run on startup.
AND people already use multiple launchers! It's not an fdroid vs playstore scenario, where grandma isn't going to install fdroid. Grandma is already installing random exe's from all over the internet. And gamers already have company-specific launchers - battlenet, EGS for fortnite, and so on. And they have an existing install base, from fortnite! Though I suspect most of their users are mobile. But it's a big leg up vs trying to crack the chicken and egg problem of no games = no installs = no games.
And yet, here we are. They can't even hardly give away games for free! They offer half the fees and frickin pay popular up and coming double-A titles for exclusivity. And yet still Steam is huge and games will release on EGS and on Steam and literally (there's a tweet with an example somewhere) games will see <1% of sales come from EGS.
So - what's Steam's moat? It's CLEARLY there. And I think it's simple that it's just brand and trust. Gamers (sorry, forgive me use of the term) are used to being jerked around and treated like crap, and they're tremendously suspicious of big game companies, since they're so good at ruining everything just to eke out more profits even if it kills the dang thing long-term.
But Steam has their trust because 1) they have a very good track record of not f'ing people over and 2) people trust Gabe because they know Valve is privately held and Gabe is in control. So there's this capitalist/shareholder capriciousness that's simply not a factor in Valve's business but is literally the entire business of EGS. Do people think Valve is here for charity? Certainly not. And yet there's absolutely this perceived difference between Valve and Epic where Valve is the "I make money by making customers happy, just like I have done for twenty years" type of money-making company and Epic is clearly driven in a much more stereotypically slimy sort of capitalist fashion.
I'll throw in one random anecdote: I'm sure everyone else saw the HN threads about the OLED Steam Deck? Where they're like, making screws easier for people to tinker with in the newer revision? That's the kind of thing I'm talking about with Valve. Gamers love Valve and Valve loves gamers loving valve (especially since it drives so much revenue).