Why they won't bring this trackball back to the market is a mystery.
As for the latter, the iPhone in 2007 pretty much set the bar for how mobile interfaces should be done and then everyone just fell in line. And on a sidenote, the trackballs on older Blackberries were very unreliable, so there's that aspect to it as well.
I also have the Logitech Trackman. I swear by it, and will never go back to using a mouse. I started with the wired version, then reluctantly bought the wireless model when I needed another one. The wired sells used now for $300.
FYI, Pledge or similar furniture wax works wonders on the trackball. I pop mine out every couple of weeks and give it a good waxing.
In the end, I prefer the ergonomics of the trackmans better because of the thumb ball. I even put a small bean bag under it so it is tilted backward and easier on the wrist (like my Microsoft ergonomic keyboard).
Highly recomend it! :)