Someone should, but I don't think anyone has.
I did send "comments" to a PUC hearing for a tiny little Telco in CA once, but never was able to find out what happened. They the claim in their filing that there were other services that offered equivalent service. I replied that they ony other service remotely comparable, PRI, was about 10 times the price
An excellent "compromise" would be a "fractional" PRI with only 2 B channels at the price of BRI (or even better allow a few different version with 2, 6, 12 B channels). This makes sense for the telco because they no longer need to support the 2B1Q format lines, and they are still adept at supporting ESF DS1 lines so that would simplify their inventory, training etc etc.
It would not be directly compatible with equipment, but it would allow one to make circuit switched data calls to all of the other ISDN lines out there in the world.
Bear in mind though, that the big picture is that all circuit switching will probably be gone within another 2 decades. AT&T HAS filed with the FCC to shut down the circuit switched network.
Sad - there is NOTHING better than getting a temporary connection that you "own" for the duration with no sharing.