These are all from the same company:
iPhone / iPad OS: Completely locked down. Only allowed to use your own unvetted software under very specific conditions. Apple is fighting tooth and nail to lock it down. Compared to Android, it’s very closed.
Podcasts: Apple has their own podcasts app, but leaves their directory open for third party apps to leverage. They’ve been silently powering the open podcast ecosystem for more than a decade.
Airplay: Only available for speaker manufacturers to implement with Apple consent. A great standard, but limited to only fairly expensive third-party hardware.
Health tracking: Use an Apple Watch, and get raw access to all of your health data. Don’t like how your data is visualized or presented? Download whatever third-party apps you want that display it in unique ways.
How does Apple think about these? Obviously there are business strategy reasons in very case, but as a consumer it gets vey confusing to not have a unified open/closed direction across the company.
I can’t speak to any of these points individually but I’m fairly certain security and privacy plays a factor in how some business units operate. Apple says it always tries to do what’s best for the customer but the problem is there are lots of different types of customers, needs, and wants so they optimize for the largest segment which can alienate other segments like power users, etc. I would also imagine that it’s a lot harder to implement a unified product strategy operating at Apple’s current scale.
If I were to draw a line, “what are devs allowed to do with your hardware” and “what are you allowed to do with your data” would probably be the categories.
iOS is locked down because a bad actor dev poses a huge security threat. The Mac App Store is similarly locked down, but the Mac itself isn’t - for historical reasons mainly.
But you’re generally allowed to do whatever you want with your data. Podcast URLs are public data, so Apple really couldn’t lock it down if they tried. And your health data is collected for the purpose of being able to share it with third parties, so it wouldn’t make sense to lock it down.
Regarding standards like AirPlay though, I don’t think it’s as much about “consent” as much as whether a manufacturer wants to cough up the $4 or so per device (AirPlay) to license the IP. A $20 speaker will just use Bluetooth, because they’re not going to pay 20% of the MSRP to Apple. Higher-end stuff will build AirPlay in, as the profits cover the licensing. I get the feeling the MFI stuff with cables and such is very similar. Apple wants their cut in order to license their tech - but I get the feeling they’d license it to just about anybody that meets their basic criteria and can pay up.