Apple's been like this forever, it's only gotten much worse since the late 2000's and the launch of the iTunes App store. Even in the old days, when Mac Classic existed, Apple would change its mind about stuff for developers all the time. Anyone remember OpenDoc and how that was gonna change the world? Apple's favorite thing to do is tell developers it's got the next big thing (Newton), next big language (remember Swift?), or the next big tool (AR). They hand this out to devs, devs eat it up, and like 1 or 2 years later, they either spring said thing like a trap no one can escape from, or they just give up on it and act like it never happened and move on, leaving developers with useless new skills.