Big problem with Step 5 - people couldn't run Windows on their Macbooks except under emulation. That would be a deal breaker for a lot of potential customers (pretty much all the gamers for example) and Apple knows it.
Personally, I don't think the transition to ARM on the Mac will happen any time soon. Apple will just try to convince more people to buy iOS devices instead.
I don't think ability to run Windows natively is something that Apple considers crucial. Sure it is nice, but not a dealbreaker.
I believe the main reason Apple migrated away from PowerPC was unreliability(delays, heat, speed etc.) from the supplier and progression not compatibility with x86.
>That would be a deal breaker for a lot of potential customers
Today it would be, but mobile is really taking off. Who knows where we'll be in even 2 years. Maybe by step 5 the remaining things we have to have windows for (e.g. Office) simply wont be a requirement anymore.
And to be frank, something like Office should be non-demanding enough to be fast enough emulated. (Of course software gets slower faster than hardware gets faster..)
Personally, I don't think the transition to ARM on the Mac will happen any time soon. Apple will just try to convince more people to buy iOS devices instead.