Indeed, I would be VERY happy to see another WipEout on the PS2, but I'm afraid it will never happen. Imo Sony just can't afford to mess up another PS2 WipEout title like they did with Fusion - that would be devastating for the brand WipEout is for them. That's why I think they're afraid to do another title on the PS2.

Another argument is a simple economical one, I think: As you said RR, the PS2 has already been sold over 100 million times in the whole wide world. So I guess Sony already made their profit with this console and is now focusing elswhere (PSP, PS3) with their efforts. They have to really push the PS3 to keep up with Microsoft's X-Box and a game like WipEout, which has gone platinum sales with every single release of the series (except Fusion and 3SE if I remember correctly), will surely help to increase the sales of the new PS3 console. So my guess is that Sony might watch the PS3 sales statistics and have kind of an ace up their sleeve with a new WipEout release to boost the console sales if they don't go as expected.