>Taking Apple at their word here, I still don't get it. Can anyone explain the argument they're trying to make? As written it just sounds so ridiculous (but I'm still trying to understand it).

There are at least three aspects to this: active attacks, negotiating power between various actors, and platform maintenance.

1. To the first, certain classes of attacks and malware are dramatically harder to execute on locked down platforms like iOS devices than on open systems. Remember, on the PC or Mac enormous amounts of real world risk isn't the result of 0-days but social engineering, pressure, user error or laziness, etc. On iOS, it's simply impossible to just give somebody root access. The user doesn't have it. It's even harder to have a persistent root kit, let alone go down below the kernel. When there are exploits, the owner community as a whole tends to see and have deployed upgrades faster. There are more barriers to the kinds of low effort mass adware and the like that plagued many non-technical (this does not mean stupid or undeserving) people before, like the classic of opening your relative's browser and discovering a hundred competing searchbar and ad injecting add-ons and such. And on and on.

Of course, there are security issues that can arise from this too. And if a player is more powerful than Apple is (like a major government) then the whole thing can go very bad, because now there isn't any way to bypass that either. On balance I think the long term risks are higher with no owner controlled root cert like the current situation, but we shouldn't be blind to the fact that Apple worked to solve a huge problem with computing that the tech community were really assholes about (me included to some extent in the 90s, I remember the BOFH type admin and jokes that went around hell desk quite well). There is some baby amongst the bath water.

2. To the second and per above, that Apple has a secured position as powerful player on the iOS platform shouldn't obscure that there are other very powerful players vs the normal user. Many people find certain things like Facebook effectively indispensable. And individually they lack the weight to negotiate. Facebook and the like do not give a single shit about you individually. If you tell them "you better stop XYZ tracking or no more service from me!" that likely won't even get a reply. But Apple's control means it acts as the focal point of hundreds of millions of very valuable users combined. Apple can say "thou shalt disclose privacy practices and formulate and obey a policy" or "thou shalt not have persistent device traction" and attach an OR ELSE to it and actually have it stick. But if a player of Facebook's scale could then just say to everyone "you must go and sideload Facebook Store and grant it full permissions to keep using our product" that power might well completely dissolve. In principle government could be dealing with some of this, but government is often pretty slow, heavy handed, and faces its own problems with corruption, lobbying etc.

3. To the third, while Apple is obviously making plenty of profit and some of their resources are obviously going into irritating bikeshedding UI-cycle stuff, that shouldn't disguise that upkeep of a modern networked platform isn't free. There really is a major cost to keeping up security, to developing and maintaining system frameworks, infrastructure etc, and then keeping up with that for years after a product has been sold. How that is paid for also has implications for effectiveness. It's not necessarily feasible to build all of it into hardware pricing. If users are asked to pay (remember, paid OS upgrades were once the rule in the proprietary world), lots of them won't, which means the platform becomes more fragmented and more people miss out on critical security updates sooner or later. Having it be part of developer prices might be a least-bad way to do it. There is some link between those who benefit most and those who pay most, and it doesn't create the same negative incentives for users.

People mock the "Apple Tax" but honestly paying taxes for infrastructure isn't always a bad idea. If anything I wonder if Apple shouldn't actively lean into that and announce they're going to make it more progressive, with 0% fee for the smallest fish rising to the highest amount for the biggest ones. But it too depends on some level of enforcement, same as taxes IRL.

----

Again, none of this is to say there aren't major, obvious downsides to the level of control Apple has too. Their accountability is limited, and their incentives certainly aren't all aligned with their customers. Their control has been used for anti-competitive ends and moving into other services that should be more competitive (backups being a simple example) with negative effects (not just money, but lack of E2EE encryption). I do think there is room for legislative improvements. But it's not entirely simple.