A recent analyst report claimed that Apple's 2023 iPhone will be the first to feature an Apple-designed 5G modem. That's something that's been coming ever since Apple bought Intel's failed modem business and Apple does love to have control over as many of the chips inside an iPhone as possible. But an Apple modem does have another potential home – MacBooks.
People have been begging Apple to put a cellular modem into MacBooks for years. Probably since before the iPad got it, but my memory isn't that good. It's yet to happen, but could an Apple modem fix that? Possibly. But probably not.
As much as Apple's wish to control the chips does sometimes inform design and feature set decisions, I don't think that's the case here. Apple could have put a Qualcomm or Intel part into a Mac before today. Other vendors already do it. The problem isn't so much hardware, but software.
I'm not the first person to say this, but macOS just isn't yet set up for an always-on connection – especially when those connections are more often than not, metered. Having a cloud backup service crunch its way through someone's data cap because it didn't know it was on cellular wouldn't be a good look. By contrast, iOS and iPadOS both know all about cellular connections and have the mechanisms in place to control their use. macOS, not so much. It needs granular control of apps so as to control the kinds of data connections they can use at the very least. Some sort of Low Data Mode would be cool, too.
Sure, Apple could no doubt add that kind of thing to macOS. It's got some very capable engineers after all. And I suspect it will, one day. But if software is the blocker here just as I think it is, it's nothing to do with modems and an Apple modem won't unblock anything.
Which is a shame, really. Nobody can argue that a new MacBook Air with 5G connectivity wouldn't be super sweet.