We all know the saying: don't buy a system for a single game. It's kind of true. It'd be a very logical decision. However, we all know that there is something that will instantly push us over the boundary without room for the slightest hesitation.
And so, what games are there that will instantly convince you to buy a system, spend hundreds of dollars on the needed accessories, even if you have no other reason to possess that system?
You don't have to name any system, but it can be any game that is unannounced, frozen, cancelled or merely exist as concepts.
For me it'd be [redacted due to mental trauma] 3, Persona 5, Valkyria Chronicles proper sequel and Warcraft 4.