The thing is, a new series doesn't have to build off ENT. If anything it will either build off the movies (most likely) or off the TNG-era continuity (unlikely but possible). In either case it will be able to be connected to previous success rather than failure.
Remember, TOS was a network failure, but it still managed to spawn the rest of the franchise. The cancellation of ENT after four seasons, just like the cancellation of TOS after three, and TAS after two seasons is not enough to consider the franchise as a whole, a failure on TV. In fact, I would say that it's the most successful SF franchise in the history of TV.