Isn't that the point? People would like to own an Apple product instead of paying for it and then never getting the keys.

To be precise, it's not the hardware but rather Apple's operating system software which is restricting what software applications can run on your device. Do you really own the iOS operating system? No.

I don't know precisely where the line is between owning the literal physical atoms and not owning the literal binary blobs of software, but agree or not, it's well understood that buying the right to use software is not synonymous with owning the software. I feel like the hardware–software distinction is a difficult one to square in the context of "owning an iPhone."

Does owning the atoms of your phone entitle you to a mechanism for side-loading your own operating system binaries? I think so. If you buy hardware, there should be a reasonable mechanism for wholesale replacing the supplied operating system software with any alternative you like. Should Apple be required to document how any of hardware works? On that I'm ambivalent but I lean towards yes. But as for how iOS works, I personally think that's regrettably out of scope, because owning the hardware isn't the same as owning the software.