Is modern warfare 3 the last modern warfare game?

Answer 1

no

We don't really know for sure at the moment, but my gut feeling is that it will be the last, whether Call of Duty decides to change the name, Infinity Ward is fired (for real this time) or Activision simply gets tired of it. We'll see as the time passes.

Infinity Ward was brought by Activision back when the first Call of Duty was released. The only firing was done when the top Infinity Ward management tried to get a higher profit sharing amount. In November 2013 they will release a new Game. It might not use the Modern Warfare Name or the Call of Duty series name, but it will be an Activision released game made by infinity ward