There is almost zero point in making a crazed transition. PPC to Intel yes there was a point and the pain turned out to be worth it. ARM chips are a long way behind intel for one, for two the loss of Windows and Bootcamp would be a significant downside (And you do know when Apple went to Intel their Mac sales picked up, partially though the security of being able to use bootcamp for PC switches), software issues, as it took a while to get good intel software that matched everything on the PPC, then there is software that doesn't get rewritten and that causes nightmares when apple drops virtualisation aka Rosetta.
The ARM chips are so underpowered compared to intel that OSX would probably have to become far more limited to cope with the lower processing power. In fact a move to ARM would probably mean a move to many iOS conventions, including being locked into the App store, lack of customisation etc.