Apple still has a pretty solid ecosystem that makes it hard to break out of. For example:
airdrop and sharing in general - experience sucks pretty much anywhere else
watch, phone, and laptop all working together - iMessage, notifications, etc
iCloud - the experience is essentially seamless if you use all Apple products
I don't think people will be leaving Apple anytime soon, and those who don't use it probably don't know what they're missing.
I'm personally on Linux and it works well for me, but I recognize that people tend to stay where they're at, and I think Apple is probably more attractive to people who decide to leave Windows than Linux is (unless they need games, and Linux still seems to have better compatibility).