Could possibly be that there were many Eubera useres who did not want to be part of a trial and restrict themselves for two years.
Outside of getting FDA approval, the biggest hurdle will be getting doctors to RX and diabetics to try Afrezza. The marketing of it will be extremly important. And hopefully diabetics will accept and embrace the delivery system. A cult like appreciation, not unlike how apple fan bois act, for the device would also be welcomed. Anyone interested in going to an Afrezza store to talk to the Afrezza genius? :P