^^ Because he won't get the republican nomination. So if he runs, it'll be as a 3rd party candidate, taking votes away from the Republican candidate, almost guaranteeing obama's reelection.
Unfortunately in this media age, Ron Paul is unelectable, and won't ever be president. I do like his role in politics though. His voice gets debates started that would not otherwise have been started. His voting record, while commendable on it's surface (never voting "yes" on a single tax increasing bill, regardless of it's other content) is not really having a "spine" or leadership, it's ideology plain and simple. While he's right most of the time, if you watched the last (R) debate on Fox, every candidate said they would veto any bill that raised taxes, even if it was 10:1 spending cuts to tax increases. This ideology would certainly be extended to a bill with 100:1, 10,000:1 etc, which is not leadership. If you came to me as president with a bill that cut spending, ended all of our wars, made our borders bulletproof, incentivized business like eliminated tax on repatriated profits, permanently sets precedent to end cap and tax, enacts a fairtax or flat tax, etc, and the only stipulation was that everyone making over $3m a year paid in $1.00 extra in taxes, I'd sign the damn thing. (and this mindset could be extended to more reasonable legislation brought to my desk as president)
Ross Perot was before his time. If he came out in 2016 or maybe even 2012, he would be president. The atmosphere wasn't perfect for him back when he ran like it is now.
The initial video is the exact reason why Neil Boortz says that the main thin Ron Paul has going against him is his supporters. A lot of them are rational liberty minded people like myself. But a lot of them are...well...like that guy in the video, and make their over-enthusiasm public.