The high price of MacBooks is treated as a status symbol and the marketing department clearly knows as much, so I don't think they will be willing to give that up, so I lean towards your second option.
Why not got the same road with an MacBook SE? I even think this will be the first product out the pipeline.
MacPro buyers usually don't want to be beta testers and will probably be the last to transition out once horsepower is clearly there with mesurable gains.
The iPhone SE is less a "cheap iPhone" and more "an expensive basic smartphone". Far more people upgrade to it from a low cost Android device then downgrade from a different iPhone.