I wish that were so... unfortunately Windows still has the Desktop userbase majority by a wide margin, and that doesn't seem to be changing despite Microsoft's many steps towards making computer owners' lives more difficult. "Windows Genuine Advantage" that limits your ability to change hardware in a computer running Windows, licensing confusion concerning running Windows in a Virtual Machine, version confusion ("home", "professional", "enterprise", "ultimate", etc), UI confusion with Metro and the Office "banner"... and so on.
I wish Linux were "the answer" to this, but I've been running it on the Desktop since 1998 and I know it's not. A user trying to switch first has to go through a painful process of figuring out what programs they can use to do their daily tasks -- because they're not going to be running Internet Explorer or Outlook anymore, and the new programs have a different menu layout and (for the most part) different shortcut keys. If you've been working with a Linux desktop you've probably forgotten just how painful this transition was -- and it's not trivial. For people that are "stuck in their ways" and get anxious when they feel lost, this in itself is sometimes an insurmountable challenge.
Also the Linux ecosystem is very different, mostly relying on volunteer efforts with a few paid developers on the side. Being that this ecosystem represents less than 5% of the market, it's not an ecosystem that would be able to cope with the other 95%+ of the market suddenly needing support. And because it's mostly volunteers that help, users first need to figure out where to report issues (which isn't always easy), then there are issues concerning user demads vs helper pushback, sometimes leading to rudeness and communication breakdown, occasional elitism or ignoring problems, etc. It's "a different world" than Windows users are used to in that respect too.
And when you say "Or Linux", if the users given that advice knew to they'd ask "which one?" (i.e. which distribution?) Yeah... that problem too. Which window manager / desktop environment? That too. Etc.