Do you think anyone using adsense and blogspot have massive amount of blogs in a network. Like how many blogs for one person?
I know people that have 100 sites So yes i think is posible (but from my point of view i don;t understand why should somebody do something like that)
Many people use blogspot, but I think revenue share will be lower. Better to buy your own domain for less than $2
Maintaing a bunch of sites and making sure the quality is good so people actually come back is a PIA. I usually develop, test, if traffic doesn't seem to be interested, I send it back to parking. Overdeveloping is something I don't like to do.
its good to have both a blogspot and your own domain and hosting.. make backlinks for all sites from blogspot to your site. and submit both to SE