It actually all depends on how much will PS4/XB1 be available on the market and how the release of next gen consoles will affect the sales of current gen consoles. But it will definitely be very close to what PS3/360 did. So, I would say that PS4/XB1 will sell around the same within a 1-2 million margin of error in any side.
I'd say the recession will lower sales of the next generation consoles depending on their launch price. BUT the people who buy a console at the start of a generation is very different from those that buy one at the end of the generation. It depends how quickly Sony and Microsoft move from one gen to the other. It is also way overdue for the PS4 to have a price cut. But at this point Sony is probably just trying to get as much profits as possible.