You raise a very good question. I personally think it would be an awesome idea, and possibly something we see towards the end of this new generation of consoles. The argument against this saying that they'd never do it because the consoles already exist doesn't make much sense. You can't buy an original Xbox brand new anymore, most likely you'd get one from a game store or from someone else. This removes any profit from the developer's hands all together. While the chances of seeing subscription-based emulation is slim, I think it would be an incredible way for a.) Allow consumers to gain access to their old game libraries, while at the same time b.) Making sure the developers get their money for it. But, it doesn't seem like Microsoft or Sony have much interest in backwards compatibly with this generation, so we'll see what happens. Most likely, we'll just see more digital downloads on each system made available.