While I think of it, where Apple leads the field is with accessibility. Windows isn't close, and I'm unaware of any Linux product in widespread use.
I use Linux daily and nearly every server I have used has had Ubuntu installed as standard, also all Android phones use a Linux based system. To round your argument of about Linux, being a Mac user I am surprised that you didn't realise the current Mac OS is based heavily on a Linux and Unix kernel. Tend to point to the fact that the Mac isn't a mainstream product under your criteria for a Linux product