I don't think it is possible to have a locked down development machine. You have to be able to run arbitrary code on a development machine so they can never lock it down like iOS is.
There are plenty of other ways they can be less open and hackable than Linux but it can never get to the point of the iPhone.
That’s a reasonable take. The never part seems strong though.
If I may offer a slight consideration? “arbitrary code vs arbitrary signed code”.
What’s realistically stopping Apple from requiring all code and processes be signed? Including on device dev code with a trust chain going back to Apple and TPU / Secure Enclave enforcement
That's confusing "will boot anything" with "will run any userspace software".