As the others have said, linux isn't a company, it's an open-source community. Nobody owns linux, thus nobody directly benefits except the users. So, what you should do if you would like to see more people using linux is to found a linux users organization and collect dues and donations to fund an advertising campaign.
Companies like IBM advertise linux only because they are touting it as a competitive advantage over other Unix OS's and Windows. Really they are advertising IBM services, and linux is just a reason why they are better and cheaper.
Sure, maybe some of the distros like Mandrake and Redhat, and some other linux software manufacturers like Ximian could band together to advertise outright, but as others have noted, that is quite expensive. They DO currently advertise, but using more guerilla-like tactics than the brute-force $10-billion ad campaign. For instance, Lindows made a huge marketing gain when they teamed up with Walmart.
For now, the support market is mostly limited to enterprises (hence the IBM ads). That is where players such as Redhat are directing their marketing. They would have no driving reason to advertise to consumers, since most consumers do not sign huge support contracts. Lindows is playing that market with their $100/year contract, but most users scoff at paying for a free OS, even though they say they want more support.
The biggest way linux is going to get to the average consumer is through preinstallation on new computers. Several distros have tried partnerships with hardware manufacturers such as Dell, but they weren't too popular. The Lindows/Micron/Walmart deal is an example of this. And of course the biggest proponent of this theory is Microsoft, who mostly became as big as they are simply because of preinstallation.
So, I hope that sufficiently answers your question why you don't see commercials on TV advertising the features and ease-of-use of a linux desktop computer for consumers. It'd be a cool idea, but if you want to see it happen, you'll have to do it yourself. It's sort of a catch-22... the distros can't afford it until linux gains more momentum, but the quickest way to gain momentum is through advertisement. They're doing the smart thing though and finding alternative ways to increase momentum.
In the meantime, feel proud that you are smarter than the average consumer, and spread your wisdom to others. As krale implied, that's the best form of advertising. The word about linux spreads virally from one satisfied user to the next. This is something that Microsoft fails to understand, and cannot combat even with a constant barrage of commercials. It is based solely on the quality of the experience and the desire to share it with others.
Sincerely,
Tom Anderson
CEO, Order amid Chaos, Inc.
