The authorship information has nothing to do with hosting your content on Blogger. You can publish your work anywhere you choose and enable authorship by following the instructions here:
I've done that. Pretty easy to set up, and it improves your visibility in search results, since you get a picture.
Authorsure is a good plugin if you use any Wordpress sites.
So basically, Google are using their control of the search market to pressure people into moving their actual content under Google's control by offering to rank them better in search results if that content lives on Google's servers and helps feed Google's data-gathering engines. Remind me again, when did they change their motton to "Be Evil"?