[snip]
Because Linux may be great, but it's not ready for the desktop. And, frankly, it will never be. It's good, stable, light and fast. As an OS, it may be the best in the world. But then you need the desktop environment, the software, and everything else to have a whole platform. And then Linux fails miserably, while OS X and Windows succeed.
That's the biggest problem with most Linux disributions. It has lost its way by trying to be a replacement for Windows and OS X. They never should have tried to go down that road. Now distros are packed with all kinds of bloated software that may or may not be necessary, drivers that were poorly and hastily written to support as much hardware as possible because someone might complain if their special snowflake laptop isn't supported, free versions of proprietary software that offer 50% of the functionality, etc. In some cases, they just throw in proprietary software anyway.
I may ruffle some feathers with this, but trying to attract the Windows and OS X crowd means they have to hold the user's hand and do everything for them. All the software must be preconfigured to work immediately for every hardware combination possible and replace the user's favorite Windows/OS X tools perfectly, all without forcing the user to touch the command line. That's an impossible task without a dedicated development team working full time on the issue. Stuff ends up being thrown together from hundreds of different sources, inevitably doesn't work properly, and the user complains about it.
A better aproach would be to do what Arch, Gentoo, and some of the BSDs do. This is the OS and if you don't like it, use something else.