The odds are low, but we're kinda skirting the real question here: What does Valve have to gain by allowing an emulator on the store anyway? It's free so no platform cut, it's open source so it's unlikely to ever be monetizable, and it's legally dubious on top of all that. If this was some billion dollar piece of software like COD I'm sure Valve would fall on the sword like Sony did. But there's literally nothing to gain here except headaches.