I suppose there's some truth to that as long as you recognise that for Apple, profits come first. This whole new "private & secure" thing on their end is pure marketing/business.
They didn't give two shits about it until they realised that it was a major issue of their competitors, now it's become their core features/marketing. But don't think for one second that the protective wall won't spring a leak or two if it can make Apple a profit.
Apple's dominance also comes from them cornering every possible market they can, they want to do everything themselves and monopolise as much as possible, their recent step was designing their own processors, the debacle with them trying to make their own cellular modems etc. Maybe they'll go for displays next but Samsung et al are so far ahead on that game.
If Apple allows sideloading apps in any way that is easily accessible to the average user, then
(a) Meta will insist their apps are sideloaded to enable privacy violations. Right now, they cannot say goodbye to iOS users. They could say goodbye to the small percentage that refuse to sideload (or even just put a worse version in the store to those people with enough new features to push most people to sideload.).
(b) Chrome will be sideloadable. Which means web developers will be convinced "sideload Chrome" is a reasonable fix. Reinforcing spiral and soon Google owns the browser in a way that is the envy of 1990's Microsoft. Keep in mind they managed to turn MS's Edge from a third browser to a Chrome skin. That's bad (see Manifest v3, WEI, etc.).
The list goes on, we could talk about Epic and games and store exclusives.
To say nothing about having to debug malware on my family's devices.
Back in the days when TiVo was a thing, I built a MythTV box including all the troubleshooting of a capture card, X windows settings, getting a remote to work, etc. to the point where my non-tech spouse could use it like a set top box. It even looked like a set top box. This was when Netflix was DVD by mail.
The last Windows laptop I bought bricked itself in a week, the Amazon stick needed constant reboots, I don't care about side-loading apps/widgets/software on my devices - I want them to be like my refrigerator and just work. AppleTV devices are much better than others. Once you're in the Apple walled garden things are much easier on me as an end user. There are seamless transitions from device to device if I want, sharing between them is a breeze. Sure other platforms are "open" or might have more advanced features, but I don't want to waste my time doing tech support having the BeenThereDoneThat™ patch.
Edit to add: "open" usually just means you have countless versions of "standards" to try and get things to interoperate. I deal enough with that at work to be turned off from dealing with that at home when I just want to chill and consume whatever nonsense I'm into.
One started a platform with an upfront communicated commission rate that, at the time, was literally received with applause because before that the rates were significantly worse for developers and has never raised the rate in its entire history (instead lowered it for certain circumstances).
The other is a bait and switch, luring people onto the platform under one set of rules, only to pull the rug from under them years after the status quo was established and change the rules to impose a commission that didn’t apply to them until now.
One is hard to argue as an anti-trust violation and the other is pretty much a textbook example.
I personally think Apple does things correctly, and they do charge a premium, but they sell good products rather than requiring more of your time and energy (ads)