My guess is only the lower end macs will move to ARM till atleast the Apple 14z or most likely Apple A15z. Macbook Pro will be as is for a while. This is about 2 years too far out.

Also intel should be supported for a couple of years once the new ARMs are out, and you wouldn't be obsolete till the lifetime of your laptop. At the end, you may even end up with a Apple memorabilia.