As we've seen with recent mac issues, they seem these days to Only Just Work.
Some flavours of Linux just work these days, see other comments. There really is no need to tinker these days, but if you want to tinker, you can!
But a hugely underestimated cost is the cost of moving away from Apple. Watch, phone, tablet, music, accounts etc makes it an ecosystem. It's not a simple computer, Apple is a brand that integrates with lives.
Of course just how much of the population don't care about privacy so long as they can use a nice UX, many people will not care about Free Software so long as they have a good experience. Linux on the desktop is not going to win UX wars, just like how duck duck go will not win the search wars.
People don't use Linux because it has a better experience than Apple! There are other reasons.
In the future when users can only rent Mac's and not own them, people will still be saying the same thing: I don't care that I don't own this thing, I just want it to work, and it feels better than this other thing.
When I was younger, I enjoyed debugging all the weird issues on Linux. Now I value my free time way too much.
I'd rather pay a premium for a device that Just Works. I can have a separate hobby machine I can fuck around with and compile drivers and stuff, but the machine I do my work on? It needs to work and work well. Every minute I spend debugging some driver or fighting the trackpad is a minute I'm not earning money.