A reboot what? Michael Bay quitting the Transformers franchise what? Are you guys writing those things really serious?
Do you get the simple fact that he is not just the director but an executive producer of the movies, he was selected by Spielberg the other executive producer as the perfect director for the job and he has agreements and signed contracts that ensure him a good percentage of profits on both movies and merchandise?
He would be just crazy to quit the business just because some haters and bashers on this official forum or other forums are telling him to do that or so called professional critics paid by competitors are telling him to do that... that is not going to happen unless he goes out of mind I really don't see how he would ever want to commit a financial suicide, really.
After Transformers3 the franchise could continue with an high budget live action tv series featuring CGI by ILM like on the first movie maybe, to bring down costs--by 2012-2013 the CGI level of the first film should be cheap enough for a tv series, maybe a miniseries one like Taken of just 10 episodes that was produced some years ago by Steven Spielberg... far from cheap at the time.
And then by 2014-2015 they should release Transformers4 and start a new trilogy maybe set 10-15 years in the future or more featuring the sons/daughters of Sam and Mikaela characters that would be Headmasters and so on, that would stay true to various versions of the anime and comics that way.