It would be irrational to expect that PS2 runaway success can go on for ever.
But then, from that perspective Apple is not doing too good with iPad either. They had pretty much 100% of market in the first year or so when iPad was introduced. You can only go down from that number, and they did.
Now it also depends what will MS and Sony do with X360 and PS3 in the next few years. If MS does the same as they did with original Xbox (as in discontinue it right after X720 is introduced) and Sony does what they did with PS2 (as in keep making PS3 until PS5 is about to be introduced), Sony still might have a winner in this console generation. Unlikely, but not impossible.
So, would you place Sony and Apple in the same league as each other today?