I still have my original PS2, bought on release day (and I didn't even wait in line). Runs fine. People also remember that the PS3 is backwards compatible witht he biggest gaming library of any company; all of the PS1 and PS2 games. Three generations of games on one system. That's a huge selling point.
Secondly, if MS doesn't make any serious gains in Japan, it hasn't a chance in any long term survival. The Xbox is still around because Microsoft ate a TON of cash to keep it going. Are they going to do that twice?
Third, Sony didn't do anything to Nintendo. Nintendo did it to itself. They shot themselves in the head with the N64, when it was clear the CD-ROM games were the future. Had Nintendo's partnership with Sony stayed intact, and the Nintendo Playstation been released as planned, Nintendo would still rule the gaming world.
Lastly, how many PC gamers, who spend thousands on their PC's, are going to shell out cash for an Xbox 360 and its games, when many of them are available on PC?