we've heard all these arguments many times before. Don't think what you're saying is new at all. We've already thought about it, discussed it, and come up with our own predictions. The PS3 finishing last is by no means a universal thought on these forums, in fact the most popular theory is Wii-PS3-Xbox360.
However, you're not really bringing anything new to the table here. We all know all these facts. Most people just think that it isn't enough for the PS3. You say 2008 is the year for the PS3. I agree, it's the year that the PS3 will have to really put the effort in if they want to overtake the Xbox360. However, no matter how well they do, the Wii will still outsell it in 2008 by a lot.
The number of people who expect Gamecube numbers out of the PS3 are quite small. It has actually gained a bit of traction. However, trying to judge anything from the recent sales are impossible, they are holiday fueled, and no one knows what's going to happen to the PS3 once January hits. I personally expect N64 sales levels lifetime for the PS3.