The web was just a tad simpler over a decade ago when Google 'launched' initially. In fact a lot of the web's titans like Ebay, Paypal, Google, Amazon etc.. were 'launched' during a different era if you will... It was called the 90s. I'm not so sure the same rules apply today. One should at least consider that things have changed in this regard.
Every other product Google's come out with since then was 'launched' in what we'd consider the 'traditional' way. Gmail was invites, Wave is invites.. Maps was released with a lot of fanfare.
What I do agree with is that immediate or front page media attention after launch is not indicative of the app's future success. In fact it seems the more hype things have in the beginning the less staying power they seem to have in the long run but I suppose it can go both ways and there is no one rule..