Don't ever bank on a one console future, and if so, Nintendo is as good as dead in the water. For a truly uniform experience, the PS3, as of now, is likely the prototype of a one console generation. The PS3 did a lot right with hardware, which was my main reason for purchasing it first, with Blu-Ray, a large harddrive, and optional motion sensor. The large processor and graphics capabilities are even better for the developer. The problem with a one console future, other than price gouging, is the lack of innovation. The Wii, though not my preferred console, did a lot right with innovating controls. The problem is some games just do not work with this control scheme, for example GTA 4. I tried the SixAxis tutorial for about 5 minutes until I turned it off. With the Wii motion sensing this would be impossible and would have turned off plenty gamers. With the loss any loss of sales, that kills the desire to innovate.
Finally, a one console generation means one good thing for the gamers = AWESOME games. Instead of having hardware battles + software battles, the companies will fight for the best games. Sadly, Nintendo will have to compromise some of their ideas for a mass appeal, such as more games like Wii Sports, which will not appeal to the hardcore gaming audience. In fact, a single console generation will pretty much scrap the hardcore gaming audience because those gamers are such a small fraction of the overall target audience that there is no means to market to them. PC gaming will get quite a kick start from this trend because of it's customizable abilities, keyboard capacities, and variety of game options, then console gaming will be dead.