Can Steam recognize non-steam games as a regular Steam game?

[Celtic Jaguar]

Now, I don't mean adding a non-steam game to the library. I know how to do that. What I mean is: Is it possible for Steam to recognize a non-steam game that it has in its store, that you purchased elsewhere? So that it reads the game like it would as if you purchased it from Steam.

For example: I bought Witcher 3 on GoG, and Black Desert Online on BDO's website. Both of these games currently exist in Steam's store.

Is it at all possible for Steam to recognize these AS Steam games, and realize we already own them? So that they don't pop up in our queue and such, and we're able to see the pages related to that game when we click on its name? Or is the only way to do this to re-purchase the game through Steam?

[LowJack_VA1]

Nope. It doesn't work like that, at all.

[Kargor]

It is unfortunate from a user-perspective, but Steam not offering support for Origin/UPlay/GOG/whatever makes sense from their perspective. Not only would EA and Ubisoft complain if Steam started to integrate their client to make things more consistent for users (GOG I'm not sure about, they might not object), but Steam is really just Steam -- why woould they even want to support competing platforms.

[Cathulhu]

Additionally, Steam can not verify if those copies are actually legit. If it would work that way, anyone could pirate a game and add it to Steam to get achievements and stuff.

[ KARR™]

The only way for Steam to recognise them is for you to activate a cd key on Steam for that game.

If a game won't be activated, it is normally because that games publishers don't want it to be redeemed on Steam, or just haven't bothered to provide the cd keys to Steam.