However, I think Apple has been a far greater threat to Linux adoption than Microsoft. Why? Because it gives techies the *nix environment they want, with the software and hardware support no one will give them on Linux.
There is real value in proprietary commercial end-user application software. Most companies who make such software couldn't care less about supporting Linux. So if you want to use Linux, you have to use F/OSS alternatives and continue to try convincing everyone that somehow they're better than the commercial options... even when the rest of the world has agreed that they're really not.
The whole incentive structure around F/OSS development really doesn't work for software where the profit motive is in the product itself... Not some nebulous "support contract" that you don't actually need. (Which is a far bigger issue for end-user applications.)