While it is entirely possible that Sony, Nintendo and Microsoft could put off releasing a new console for a couple of years, realistically one of them is likely to decide that their long term prosperity is best suited by releasing new hardware and the rest will follow suit. Basically, by the end of 2010 as much hardware will have been sold in this generation as was sold in the previous generation, and most of the people who owned a previous generation console will own a current generation console. This (essentially) puts the generation in a new phase where the console manufacturers are in more direct competition, and it is likely that one of the manufacturers will see releasing new hardware as the best way to take consumers away from their competition.