Only way the PS3 sells 75 million is if they extent the life of the unit to about 2013 at this rate and by then it becomes irrelevant.
Everything else aside, Swanlee do you doubt that the PS3 will still be for sale in 2013? That's just six years for a console that will probably be on sale for near ten. PS3 in 2013 will be no more or less relevent (arbitrarly) than PS2 is relevent in 2007.