Since it's destroyed it falls in the can't territory and dodgy as well.Two ships can, and one was destroyed. You know where this is going. Eventually they will rationalize not using spore travel anymore. I mean, unless they are tying spores into the TNG gel pacs in some way.

Of course there will be a reason the SporeDrive isn't the travel mode of choice going forward. Not sure why anyone would think otherwise. The show isn't about making the SporeDrive the new drive system any more than the Ultimate Computer was about a new computer system. The M-5 and The SporeDrive are there to move the plot not to change the Trek Universe.