The reason the PS2 and PS3 were backward compatible was because the previous gen's hardware was in the console itself. That also inflated the price of the newer console. I'm guessing this is a good way to lower the price of the PS4 without abandoning the PS3. Now, I'm wondering if there's a way to let people play games they already own. For example, put the PS3 disc in your PS4 and the streaming service allows you to play that PS3 game while the disc is in your console. I'd imagine this would also allow you to access all of your PSN/DLC/etc. content. Hopefully, this is the case because that would be wonderful. I wouldn't be surprised if this is offered as a bonus for people who subscribe to PS+, too.