I bought the 770 when it was just released (beginning 2006 if i'm not mistaken), and it was my first real introduction to linux!
I don't think Nokia had much of a plan about what it was supposed to be. I think that for Nokia "internet tablet" mostly just meant "a mobile webbrowser". That seemed the only part that functioned really well. And it was the reason I bought the device. It was the only mobile computer/PDA/Mobile with a high density screen that was affordable (360 euros at the time).
I'm very glad I bought it. Back then mostly because I could browse the web anywhere, and currently because I learned so much about linux because of it.

The current pad/tablets are bigger, but are also much more than just a web browser. I don't think Nokia ever envisioned the Internet tablets to be used in a way that we currently use tablets/pads.
So I don't think that they are the same form factor.
I think the internet tablets are more like PDA formfactor. But because the PDA is used so differently from an iPad/tablet, nobody would call the iPad a resurrection of the PDA.