But that leaves out something very fundamental about Macs: They've always been very accessible and user-friendly. Even on Catalina, people tend to find their way around the OS really quickly, in part because lots of things they know from their phones are there as well (LaunchPad has all the apps, like on a phone, there's Spotlight, like the search on the iPhone, there's Preferences app, ...) – and you don't have to do anything to keep it running and working, everything auto-updates at night, it's hard to break things, just ... open that Macbook and use it. If you have other Apple devices and peripherals, they might even auto-pair on demand and things like that. Usually a very smooth experience.
Of course, there are lots of people who never had a problem with Linux at all ... except that when they share their screen in MS Teams, it's two 4k screens plus laptop display stitched together with a fairly complex fix that involves scripting virtual webcams, or there's no way to use the projector at something less than 100%-scaled 4K that can be done on-the-fly, or wifi stops working until the next reboot when plugging in the USB-C hub at the wrong moment, or the fingerprint sensor either never works, or nondeterministically sometimes works, or company e-mail works fine in Outlook and Apple Mail but not at all in Thunderbird, or the fans run all the time ...
I've never had a smooth ride myself trying Linux on a desktop or laptop, nor have I ever talked to anyone who didn't eventually admit to having issues like that – and while that may be tolerable for someone who values being able to use Linux a lot, it's unacceptable and broken for everyone else. Maybe there are people who actually do have a ride so smooth they never even have to touch a command line at all – but I have strong doubts.
Yet that's one of the bars to clear. With Macbooks, I never have to touch a command line (I can, if I want to, but I know no one outside of my dev/ops/research/nerd bubble who's ever actively used a Terminal). The vast majority (for a very large value of vast) of people out there have never touched a command line before and have zero inclination to change that. They don't have anyone to sysadmin for them, either.
Ubuntu on a Macbook-Air-ish affordable and somewhat stylish laptop, that'd be it, can't use those Airpods. Or any other headphones. Or play any sound at all, because for that particular sound chip, alsa needs this particular config to be set in such and such a way.
To be the "new Mac", it'll have to "(very mostly) just work" like MacOS, Android, iOS, ChromeOS, or even Windows – bonus points if it has a walled garden with lots high-quality apps and no really easy way to break out or actually break things, because that's a big feature for people who just want to _use_ a computer, not build, admin, secure and maintain a complex OS.
And all of this is deeply frustrating, because I _like_ Linux. But I hate having to put in all the work and still lose so much comfort, efficiency, dependability and ability to do things I can do easily on MacOS, on inferior hardware, without a Touchbar, without a proper touchpad – it's just not there yet, not by a long way. And if it's too much hassle for me – someone who's built a Linux router on a 200Mhz Pentium 2 when Pentium 2s were still decent machines and 10mbit LAN was fast – then I guess it's not going to work for the vast majority of people, either.