There's two layers to this as well. The layer they handle reasonably well is integration between Apple products owned by the same person (less so shared products like Apple TV and HomePods), what they do terribly is dealing with the fact most people don't exclusively interact with people who exclusively use Apple products. God forbid, some of us might even use non-Apple products ourselves.

That means that you've got a bunch of really neat features built into the operating system which in practice you can only use one time it would be useful in twenty because the other people you want to use them with aren't using an iPhone. I'm thinking here of things like Airdrop only working between Apple devices, or the support for sharing audio from your phone/TV with someone else who's also got a pair of Bluetooth headphones only working if those headphones have an Apple logo on them.