If EA and Ubisoft really want to be a competitor with Steam, they should at minimum do what Steam did for Valve games.
Pretty much since the Steam client was released in 2003, Valve allowed you to tie your previously bought (physical disc-based, mind you) PC game keys to it.
As Origin and Ubisoft stand, unless I’ve bought some of their games very recently, I’m a brand new customer. I don’t have any history with either their published or house-developed games.
While a platform may not be able to control what third-party publishers choose to do with their back catalogs, if a game exists on the publisher’s own platform and there is a list of legal CD keys in some database, it stands to reason that there’s an immediate gift of customer buy-in that you can give your marketing department.
Much like format shifting in the movie industry, making the leap to your new platform requires a significant amount of faith that you will do what you say you’re going to do for me. Not just now, but 3, 5, and 8 years from now. Both EA and Ubisoft have exponentially more game years in their catalog than Valve does. It’s a real shame to presume that their customers don’t value that.
Whatever it costs to make it so that my original Sims CD registers on your platform will be worth it, because it may convince me that I’m not being sold on a new platform at all: I’ve been on it the whole time and just unlocked new value.