Again, not every department and college do the reviews in exactly the same way, but all must do them by using processes approved by the Provost. Your fulltime faculty are assessed annually, and far more than you realize. They also may not get promoted. The problem I have with tenure is that it is an extremely politicized process, which therefore makes it subject to corruption. Furthermore, tenure was necessary some time ago, but I do not feel it is needed.
Academic controversy is respected today and seen as a positive role in academia.
In addition, professors now have other protections under the law that would prevent a university from firing them because of the things the do or say in their mission to teach. And don't kid yourself about academic freedom without some form of tenure or procedural safeguards equivalent to it. The landmines are everywhere, believe me, and the very essence of the American university would be very different without the ability of faculty to speak their minds without fear of retribution by trustees, presidents, local elites, or the just plain pissed off. Not that many do speak out, mind you. You still have to work with people.