Since the Vision Pro was released, I’ve seen some debate over whether or not VisionOS leans more towards iPadOS or macOS. While I think the answer is clearly iPadOS, it did get me thinking about Apple’s operating systems post Mac OS X. Every new Apple OS since the iPhone has been a descendant of iOS or iPadOS. The only macOS direct descendants I’m aware of are iOS and the software for the original Apple TV from 2007. Why is that?

Performance

Since they debuted their first custom chip in 2010, Apple has been touting the performance and efficiencies of their their SoCs. Many iPad chips were lauded as having “desktop class performance”. Sometimes we get so caught up in the marketing that we forget that these are mobile chips. And their performance, until relatively recently, hasn’t really been comparable to modern x86 (Intel) chips. That makes the idea of building an OS for thermal and battery constrained mobile devices based on your heaviest, least power concerned operating system not the most attractive idea.

When the iPhone was announced, Steve Jobs proclaimed that it ran OS X. And that was true, but it was a stripped down OS X, because there’s a lot of legacy functionality and cruft that Apple doesn’t want to pull forward. Note how the primary macOS UI development framework, AppKit, never made it off of macOS. But UIKit, the similar framework for iOS, has stretched to iPadOS, tvOS, and even back to the Mac, via Mac Catalyst! macOS has a rich history that streches beyond Mac OS X. But Apple has apparently decided that going forward, iOS (and iPadOS) is the new base for building a new operating system.

Software

If you’ve been around long enough to witness heyday of the Mac vs. PC debate, you’ll remember that the biggest knock against the Mac was that it had “no applications” compared to Microsoft Windows. And some of the applications it did have, looking at you Microsoft Office for Mac, were pale reflections of their Windows counterparts. What ultimately solved this problem and helped lead to a new golden age for the Mac was the open web. People, by and large, aren’t using a ton of native desktop software today, they’re happily using web apps in the browser. The net effect of this that there isn’t a ton of momentum in the developer community for building native desktop apps.

When you’re building an OS for a new piece of hardware, you know there aren’t going to be many, if any, apps available day one. The way that Apple has been getting around this in recent years is to leverage the shared iOS foundations in their new software to run existing iOS or iPadOS based apps on some newer platforms. When the iPad launched in 2010, it could (and still can) run iPhone apps in this terrible and gross compatibility mode. When the Vision Pro launched, it leaned pretty heavily on existing iPad and iPhone apps to fill the initial software gap. Hell, Apple even shipped a number of first party apps on Vision Pro as iPad apps! (I expect this to change at WWDC 2024).

The point is, that the native software momentum is with iOS and iPadOS, not macOS. People aren’t really building native desktop apps anymore. If you want your new OS to have a solid software backbone, you wouldn’t build from a desktop os, you’d build from your mobile base.

The App Store Toll

What do you think macOS would look like if Apple was building it today? Do you think it would look a lot more like iPadOS? Maybe not from an interface perspective, but you can bet it would be just as locked down. For security purposes? Maybe. Apple is on record as declaring the security situation on macOS as unacceptable . Its easy to imagine macOS being developed as an “App Store only” OS today. And that, of course, would mean that Apple would also get their, at this point customary, 30% of software sales there as well. I don’t think the (relative) openness of macOS is something Apple wants to replicate from either a security or financial perspective.

Conclusion

As virtually every computer Apple has built since the iPhone has been a mobile device, it hasn’t made sense from a technical perspective to build off the more capable, but resource heavy base of macOS for new software. And from a financial (greed?) perspective, making decisions that can lead to extracting more revenue from 3rd party software is probably hard to pass up. Its just interesting with the calls to put macOS on the iPad and Vision Pro, to see that macOS has really hasn’t gone anywhere beyond the Mac. And that seems to be how Apple likes it.