Danny hasn't decided not to extend Bradley or Crawford. He simply delayed the decision until after the season. The only players on rookie contracts that you extend are stars, otherwise, a great majority of the time, its cheaper to let the free agency process dictate the market and sign the player later.
As I understand it, Danny was negotiating with Bradley, held off completely with Crawford.
IMO had Stevens gone with the past three years of evidence and not tried to make Bradley a PG through the preseason, Bradley would have shown enough more for Danny to make an offer that Bradley would have accepted. Likewise, Crawford, put at the PG from the start, would have shown enough to at least get an offer from Danny--and the question would have been whether Crawford was going to accept what he was offered.
Both could have been steals if Danny had nailed them down.
However, it seems like it only took Stevens four games into his regular-season NBA coaching career to get the hang of it and position his players to their rightful roles. Thus, the overall cost of Stevens' education has been contained to those first four losses and maybe not sewing these two guys up while they were more affordable.