TAWS B is significantly cheaper than TAWS A. If the NPRM goes ahead, then the most common TAWS B solution will most likely be a Garmin 530W, which not only meets the TAWS B requirements, but adds a new VHF Comm, a new VOR and a TSO'd C146a GPS.
Did it just save my business money if I managed to get in to an airfield with an RNAV approach with lower minimums compared to the NDB approach? Absolutely! (And my customers are happier!)
So for the operators with TSO'd gps already such as the Garmin 155 the only option is for a refit with a 530w??
Thats a lot of spondula's for the poor operator with a fleet of them, and there are a lot of them still around.