James Michael, what you say is very true, however I think that you will find that a majority of aircraft owners (and maybe pilots) who live outside the "J" curve frequent controlled airspace far more than you think. Certainly most do in our neck of the woods. Indeed many fly IFR
If ADSB is mandated, I will be fitting it with ADSB-in.. subsidy or not, because I believe there are some very important safety benefits.
However if no subsidy is forthcoming, many will not fit ADSB (unless the mandate prescribes all aircraft) and the real benfits of ADSB will be lost.