When there are only 2 companies, both providing a multitude of features, then the more features there are, the easier you run into the problem that the features you want are not covered by both companies.

Therefore, the features should be decoupled from the platform companies as much as possible. Features should be orthogonal to the platform.

For example, imagine you cannot buy shoes separately from your pants and your shirt. If there are only two companies making outfits, then you'd easily run into trouble finding an outfit you like.

You may have friends, colleagues, or bosses who insist that you use iMessage or FaceTime. The former is Apple-exclusive, and the latter... well it technically supports web browsers, but the setup is way clunkier than just getting or sending a call from an app. Apple has internally discussed this and absolutely does not want the process of sending messages to iPhone users from Android users to be easy, lest kids buy cheap Android phones.

Or, alternatively, you want to use an item-tracker to track lost items. AirTags are the best option available because the app for it is built into iOS; whereas Android-compatible competitors like Tile or Chipolo absolutely do not have that kind of network size. In fact, this actually made Android phones slightly dangerous to use, because all of the anti-stalking features AirTags have are designed around the stalking victim having an iPhone.[0]

Or you like AirPods, which have firmware that only updates on Apple devices. You can use them with Android phones (I do), but even things like battery status require third-party apps, auto-switching doesn't work, and you can't configure all the settings the AirPods have. This also applies for MFi hearing aids, which is actually the thing that got my dad to switch off Android and onto iPhone.

Every product Apple releases is another thing Android phones can't do or can't do well, and another reason why someone who might absolutely hate the App Store would buy an iPhone despite instead of because of it.

[0] Yes, I'm aware of the Tracker Detect app. As far as I'm concerned, that's a half-measure, because most stalking victims are not going to be aware of it until they've already been stalked. To misquote Steve Jobs, it's a feature, not a product. You need to bundle that feature into something else that people might actually install - like, say, actual AirTags support apps.