We don't believe that MS Flight will be a failure, but regardless of the outcome, it doesn't change much for FS9 support, because if MS Flight will "fail" for the hard-core users that decided to stick with FS9 waiting for Flight, they'll either finally switch to FSX or P3D, some will switch to X-Plane maybe, but I don't see FS9 growing, it can only go down further.
In any case, one should really define "failure" first, if it will sell a couple of million copies, exposing 3rd party developers to a new market we couldn't dreamed of reaching before, for us it will be a success.