I was browsing the tag list and noticed theory. I was curious what counted as video game theory was so I looked. I don't see a whole lot of continuity in the questions. Two have it as their only tag, but one of those more belongs under the terminology tag. The only question I don't know how I would remove or replace it would be:
Why aren't all games available on all platforms?
So, can we burn it with fire?
One could make an argument that theory exists as a counterpart to strategy and similar to represent thought rather than practical application. We also hear a lot about "theorycrafting".
Considering we repeatedly question why the latter tag exists, though... it seems like this one is equally unnecessary.
In most scenarios, the presence of theory is unnecessary both to the question itself and to the question's place on this site - you can pretty much ask the exact same question from a practical standpoint and get the same answers. This also extends to truly theoretical possibilities, as "Is X possible?" is only different from "How do I do X?" in terms of semantics and approach. The rest of these tend to be about either terminology or game mechanics... neither of which are theoretical in the first place. As it were, most of the time the kind of question doesn't need to be tagged - identify-this-game and game-rec are outliers, not standards.
So pretty much any scenario that we could highlight theory, there's not much need point it out as its own tag. Simply put, "what if" questions don't really have a need to be specially distinct from "How do I" or "What is this" questions.
For your sole example, I'd suggest using cross-platform.
I think by theory the original poster means 'speculation'. Both answers to the question seem speculative: there aren't any links or mention of sources. Not to say they don't present rational theories.
Maybe the question is better tagged as game-development.
