If you look at how much major corporations spend on marketing every year, you see television commercials as the single most popular form of advertisement. It is also extremely expensive. The cost to run a commercial on one major station during prime time hours (in order for the most people to see it, and be effective) would be very expensive, especially since we would be looking at doing a national ad not just a cheap local ad. A commercial is a wonderful idea, but they are extremely costly, especially to run more than just once.
If you get into running it on multiple stations during one more than one time slot, the cost grows rapidly. Unfortunately, running one commercial, nationally, once, at one good time, would be a lot of money on it's own, and still wouldn't be as effective as we would all hope. In order for this advertisement strategy to be effective, it needs to be run frequently.
Don't mistake my meaning in using terms like marketing and advertisement, fact is, even not-for-profit organizations that pay for those little 90 second info blips still pay a lot of cash to run those ad's.
I don't believe we have that source of capital at the moment... Unfortunately, we are now and will continue to run mostly on free publicity from news ad's... Which can either be good or bad, as we all are more than aware.
EDIT: After a quick google search you can find that for 30 seconds it is upward of 350$... and that's at 3am... Looking at during a prime time show it can be as much 10,000$ and those slots will always be taken. The most effective way to get those slots is to pay upward of 85,000$ a year in advance and have the slot for that entire year, which in the end is about 35$ per 30 seconds... Still, do we have 85,000$?