Its not going to be his last year because the Ravens are a good organization and good organizations do not just roll over coaches constantly.
As to what they see they probably see more than you are. The job of a head coach is not just whether to go for it on 4th down, its game preparation, player development, and being able to get the most out of the talent you have. In all of those fields unless you are putting blinders on you can not argue that John Harbaugh has been exceptional and that is why his job is safe.