Sure, it might be better for the platform holder (arguable), but it certainly isn't better for the developer, and I don't buy that it's better for the consumer. Developer's should have the ability to sell and market their games how they'd like to. On Steam they can as long as they don't mind the 30% cut that Valve takes. And for that cut, Steam provides extensive developer support. From what the developer said in a post earlier in the thread, MS also provides extensive support for developers putting their titles on the MS store. On PS, for that 30% cut that Sony takes, you do what Sony tells you to do and you do it how they tell you to do it. And if that means you can't effectively market your game so that it sells well, well tough luck.
From what developers have said, Nintendo are also very indie developer friendly and next to Steam are one of the places that Indie developers actually enjoy releasing their titles.
Developer support and enablement are also one of the reasons that despite EGS only taking a 12% cut, most indie developers still prefer the Steam store. It's just easier to put your titles up for sale (including choosing how to package your titles and how you want patches for your title to be handled), easier to market your titles, easier to communicate with the people that buy or might buy your game, more extensive analytics, and you get to choose how and when your title goes on sale. As well, despite it still very much being a work in progress, Steam's backend of trying to display indie titles to people on the front pages based on what it thinks users like to play has increased visibility of indie titles to consumers. Of course, it's not perfect but it's much better now than it was 1-2 years ago, so it's obviously constantly being improved. I'd say it's at least mostly decent now (at least in my experience) versus 1-2 years ago when it was very hit or miss.
It's the difference between a Storefront that wants to help you sell your game (Steam) and one that just wants a cut of your game sales and nothing else (PS Store and EGS).
Regards,
SB