> The issues with Android are not due to the token ways in which it is slightly more permissive for users (while on the whole still being extremely locked down...); they are due to the ecosystem of manufacturers and how devices end up being deployed

I meant something slightly different wrt 'permissive', namely that the overall market execution of Android is very permissive. To users buying the product, the specific reasons why Android is less secure don't matter. The only thing that matters is that they cannot fully trust software on the device or acquired though stores. Whether its the vendors that don't update the OS or the telecom company that installs crapware or the poorly policed third-party app store, malware has ample ways to get on the average Android device, due to the permissiveness of the full chain of processes and people involved in how it is deployed and managed.

> the reality is that for the first over well-over five years of iOS existing, it was de facto open: jailbreaks were commonly available and easy to use

Agree. The first few years were a whirlwind of rapid evolution and Apple had its hands full, and Apple just wasn't developer-focused. Jailbreaks were likely tolerated because developers were hungry to try things and Apple knew the libraries on iOS weren't that great at the time. Plus, jailbreak developers were like an outsourced R&D group for Apple to pluck ideas from. However, as iOS matured, and our culture rapidly adapted to smartphones, people began trusting them with more and more personal information. The cost of not addressing security became higher and higher. Developer tools and libraries also matured in this time, so overall the negatives of jailbreaks (security) began to far outweigh the positives.

> the idea that the very existence of an ability to control your own device can thereby be shown by simple demonstration to not be a serious concern.

Concerns for security exist on a spectrum (and are weighed against other concerns in development), and concerns can change as the world changes and the product evolves.

> the business reasons are that they want a strong DRM story in order to be able to pitch content producers and developers on why their platform should get to deploy and vend their media

I've never once heard the argument that DRM is the reason iOS is locked down. It also doesn't follow given that Macs are not locked down and can get the very same media, as can other platforms.

Given Apple has consistently focused on making computers for regular people for over four decades, I think it's pretty obvious the reason iOS is locked down is simply because there's an enormous amount of bullshit that comes with having users download software from unknown sources, and that a tightly controlled platform provides a much better user experience for regular users. Any other benefits are incidental.

EDIT: After re-reading your comments, I think we're disagreeing in whether locked down = more secure. In the case of iOS, I think it was a conscious decision made to create a better user experience, and an important subset of user experience is security. As you point out with the history of jailbreaks on iOS, you're saying Apple's permissiveness then suggests they don't have that security concern and they want to lock it down for other reasons (correct me if I'm wrong in characterizing your argument). I disagree and think security was one of many concerns being balanced at the time. Also I believe the types of vulnerabilities used by jailbreaks were probably not the types typical users would encounter in daily use of a device, such as browsing the web or downloading apps from the app store. Correct me if I'm wrong on that.