demand increases as price goes down... with one very important caveat.
all else must remain equal.
don't forget that caveat b/c it is *extremely* important. all else doesn't always remain equal. for example, if the price of $10k fur is marked down to $1k, some folks might think it is a fake and not be interested. or damaged goods. or stolen. or whatever.
linux is gaining market share, but it is different and people need an *incentive* to do different things. their incentive to learn windows was they wanted to be employable - so they learned windows even if they *hated* it.
business doesn't move away from windows due to the incompatibility issues caused by msft brass in order to maintain monopoly like control over the business desktop. the consumer market will go where the business market goes. if business went 100% linux tomorrow, nobody would remember msft in about 3 years.
the incentive for me to move to linux was that i value freedom, saving a few extra bucks and learning new things. i like the road less traveled. that is probably why i chose postgres over pgsql and i ended up trying the zone diet based on a glowing referral. i'm very happy with all three choices, too.
if linux wants to compete with msft, they need the business desktop in a big way. applications are important here and msft brass did a great job lockign most companies into msft dependent applications - so this is a tough sell.