Offering something like that would be tantamount to admitting that they were wrong (or lying) about their motivation for locking the system down with no user choice, that it's for the protection of the user. I don't see that happening.
Interestingly it's popularity or unpopularity would prove out two things - both of which are somewhat of a win win for Apple:
1.) If MacPhone/MacPad is popular then it would prove that there does exist a currently untapped, unaddressed market who wants Apple HW and are willing to pay a premium but do not want the locked down iOS garden which means more money for minimal effort.
2.) If MacPhone/MacPad is unpopular then it would prove that their motivation and hypothesis was correct - people do indeed come to Apple and pay the premium precisely for the walled garden and the convenience it affords.
If its indeed unpopular you could keep it around for a couple of years as an EU regulatory compliance device. Then you can say to any future regulator who wants to tear down the iOS walled garden - we tried that back in 2026 and nobody wanted it.
