OK, here's my take on Google Me.
The fact of which networking site was better had very little to do with the transition from Friendster to MySpace, and then from MySpace to Facebook. It was more about the initial userbase that the sites targeted and how that combined with some good timing that let each one overtake the other.
Google's new site seems to have some well thought out features, and they've certainly got the marketing power to let people know about it. But I don't know if a corporate giant is going to be able to add the crucial element that made each of the other sites work, which was the coolness factor. Getting the right combination of new users established in such a way that the users were able to have a "We're cooler than you" attitude was what got the other users to jump ship and move to the new network.
Regardless of whether it can become the replacement for Facebook, Google Me is certainly going to attract a huge userbase, so no matter what there will be opportunities for marketers.
Google was certainly able to oust Yahoo when they first started and Yahoo was thought untouchable, but I think that was a different set of circumstances. Only time will tell if they can really pull it off in the social networking arena.