Most people that argue for your desired outcome can at least see that there are non-zero user-facing benefits to a walled garden. Do you really not have anyone in your life that isn’t an idealistic tech savvy power user? Apple obviously has financial incentive to maintain its 30% transaction cut, and it’s made some silly arguments to try to maintain that. However it’s also raised some very legitimate and well thought-out downsides.
At this point, the conversation has evolved so far beyond the “it’s a road!” analogy that continuing with that line of reasoning feels either ignorant or acting in bad faith, not because of any “won ground” by the pro walled garden lot, but because all that are interested in a legitimate debate know that these misleading comparisons help nobody.
Everything intelligent comes with a set of software. You can replace that software (on almost everything?), but then it's up to you to maintain the setup how you like. That's not unique to iOS.
No, of course not. We all know that the ability to run on unapproved roads isn't a "feature", but rather the inability to run on an unapproved road is an anti-feature that they built in the first place. For that matter, the inability to run playstation games outside a playstation is also an anti-feature which had to be engineered by Sony. For that matter, do you buy razors that only fit Gillette approved blade designs? So why restrictions on computing devices then?
I will give credit where its due in that Apple is upfront about the nature of the walled garden. Who knows, maybe there really is a market for cars that only go to approved places.