Again: On PC? Overall success is irrelevant if the topic is PC sales after switching to their own service.
It's impossible to prove or disprove because none of these companies disclose PC digital sales. And they're not going to. Heck, the only reason we have sales figures for Steam games is thanks to SteamSpy and Valve have gone out of their way to kill that.
Dragon Age: Inquisition was the best selling game in the series -- and Bioware's best selling game ever. One can argue this is solely due to rising console sales. Alternatively, one can argue this is due to EA's PC games doing fine on Origin. It is worth noting that the success of these digital platforms is heavily obfuscated, but that goes two ways.
In the end even though it is not same situation (but it is similar) it will happen same thing that is currently happening with streaming services and market fragmentation. People will get sick of multiple launchers so they will either stick to one launcher and ignore games not on it, start pirating games again because it will be again the easiest method of playing them.
No they won't, because launchers cost them nothing. The problem with video streaming services is entirely subscription costs. For the average consumer, buying a new game is literally as simple as installing a launcher. They have no real attachment to any of these digital platforms. They want the hot game, and will go wherever necessary to buy it.
The relationship between customers and developers is not a onesided one, where the devs can tell the customers to just deal with whatever shit they have come up with this time, whether it's exclusivities, excessive DRM, mad preorder schemes, microtransactions or anything similiar or related.
This is somewhat naive. Look at how bold Ubisoft are being about slowly pushing their games to use always online DRM. Don't like always-online DRM? Oh, well, no The Division 2 for you. No Beyond Good & Evil 2 for you. Of course Ubisoft play nice and AC/Far Cry currently run offline. Which is actually nice because always-online DRM kinda sucks. But if they wanted to push the issue, there's nothing anyone could do about it. The desire to play hot new games will always override complaints. It's all about framing. For example, Red Dead Redemption 2, when it comes to PC, could have all sorts of strings attached to it. Exclusive launcher, intrusive DRM, microtransactions to the gills, and all that stuff. People will still buy it. Because it's a hot, highly desirable game.
Some might note that Metro is a sort of mid-tier game. Likely to sell a few million copies, but nothing gangbuster. Which is true. But that's why they have The Division 2, as well. And likely more waiting in the wings. We are likely gonna see a sea of launcher exclusives at E3 this year. Bethesda will likely bite the bullet and admit Doom Eternal will be exclusive to the Bethesda launcher. Companies like Epic are gonna be using a combination of free games and exclusivity agreements to push people into a position where if they want to play some of the hottest games of the year, they have to play ball. And they have to play it Epic's way.