It basically comes down to SteamDB detective work. Each key will have a corresponding package. And each package may have restrictions to it. Using Borderlands GOTY for example, clicking on the Borderlands app and looking at all the packages that have it...
Searching through all the Borderlands GOTY Packages that have restrictions:
Sub 95290 - Can only be activated and run in AM AZ BY GE KZ KG MD RU TJ TM UZ UA
Sub 95214 - Can only be activated and run in Brazil.
All other Borderlands GOTY packages can be activated or run anywhere.
(There are also non-GOTY packages for Germany - but we'll ignore those for this discussion)

So the key you get has to be either one of the two above subs or one that works anywhere. Those are the only options unless it's a different product like a Germany only non-GOTY base game.

But each case is different. It depends on the package. They can restrict activation to a list of countries or restrict it against a list of countries for each package. And the same applies to restricting where it can be run.

So in this case Borderlands GOTY keys for the U.S., can be activated worldwide. But most stores are safe about it, so if they have Brazil or Russian region restricted keys, they often tell you that each key cannot be used in any other region, which is not always true depending on the particular package restrictions.

I think there's a long while before that happens. There are games which is priced above $50 but is not everyone's favorite like Destiny, Yooka-Laylee, etc. There is however, sufficient of Indies that look fairly decent like recent titles of Chasm, Death's Gambit, La-Mulana 2, all under the tag of Metroidvania.

Do the games deserve a look, certainly especially if you are a Metroidvania fan. Are they fun? Most of the mechanics look the same just different art. Aren't you tired of looking at Pixel Art and the games flagging "Retro"? Probably yes, and my definition for Retro games, apart from an older edition of the games, its the gameplay that should be Retro, not the art. Pixel Art is just overused at this point.

So, I feel there's still plenty of headways before they hit rock bottom. Especially with the number of games generated daily. Alot of nice indies are just piled below them that is actually interesting looking. Cheers, Cruse~

Was the worthless Titan Quest the Standard Edition or the Anniversary Edition? By the time I notice the game, its already an Anniversary Edition release.

I was talking with a few others that the Current Monthly or 3:1 exchange. For Tomb Raider, I am guessing the Season pass might be included in the reveal if you chose TR. It makes sense and it also balance out the value. I got the idea from Titan Quest DLC. Were DLCs packed in Monthlies before? Cheers, Cruse~