Hi eniac,
I'll tell you why (I am one of them).
If the Amiga is to THRIVE (rather than just linger on) it has to be available on a commonly available platform that has MASS APPEAL.
PS3 owners may get bored of playing games and want to DO SOMETHING with it. Do they really want to get to grips with the complexities of Linux? I don't think so (BTW, I'm a big Linux user at work so I know a bit about it).
Surely, AmigaOS on the PS3 would be FUN. Surely it would be powerful. It'd be an eye-opener for a whole new generation.
Amiga IS NOT going to gain popularity by only being available on obscure bits of expensive lashed together hardware from manufacturers that nobody has ever heard of. Why would anyone - except diehard Amigans - even consider spending hundreds of pounds/dollars/euros for a new Pc-like Amiga? Where's the incentive? It could well be an expensive error.
They MAY consider it if the OS is packed in the same way as a PS3 GAME (and sold in the same shops at a "game-like" price, just visualize it for a minute...). They THEN see what they can start doing with it and a new world opens up.
Truly, it's the only way.
Imagine, you buy a games console for £450 and then you get a powerful better-than-a-PC for £40. It'll take off, It will (honestly).
(I'll get off by soap box now).