Surely both will be in the pipeline at some point. Do you think everyone will "trust" the new fuel right out of the gate?
Also, I believe many of these formulas have been developed by specific companies. How many refiners will they allow to make the product? How willing will those refineries be to develop a new manufacturing process and how many will just say "the hell with it - it's not worth it for this low volume?"
100LL isn't exactly setting any volume records as it is. The replacement is also likely to be more expensive, even further decreasing demand... Death spiral.
Jet A supplies will be solid as long as there's oil being pumped out of the ground. It would be the "safer" bet if a reasonably economical diesel were available.