As far as my guess would go, all Iwata meant by his statement that "the current systems have basically reached their limits" is that it's time for game companies to start focusing on making solid games with the technology they have, rather than putting so much money and time into developing a system that is 3x as expensive as the old ones with nowhere near that value in improvements. Like kingvudu said, what he probably meant was that the jump from this generation to the next will seem extremely minimal next to the jump from SNES/Genesis to N64/PSX, and even the jump from N64/PSX/DC to GCN/XBox/PS2. While there will be improvements that are helpful (processing power, primarily), we're not gonna see the kinds of jumps (especially graphically) that we did in previous generations.
If that's the case, I think Nintendo is the company that can benefit from it more than anything. They've always been about quality games, and if my guess is right (which is probably unlikely, or at least only a fraction of it), their dedication to quality games will be what brings them above and beyond anything Sony could ever do, or anything Microsoft could ever pay for.
And in response to the newly posted above me thing by Guitar Smasher, he's exactly right - building this kind of hype and mystery is exactly what they need to do.