Sure, if all of these people had a dollar a month. In third world counties, they don't have that much. And this is counting kids, so really it's a couple of dollars a month for a lot of people. And the more poor nations don't even see a few dollars a month.
Let's just cover America, since we all have a pretty good baseline for how much a dollar is worth, most of us live there, etc. Let's give everyone healthcare. 2.5 trillion divided by six billion... Ok, that's 416.67 months to pay off one year. Almost 35 years. That's everyone in the world paying for just America. That's a bit unfair. Let's have America just pay for America. Last census puts us at 304,059,724. I'm gonna round that up to 305,000,000. It would take 683 years to pay off 2009's medical spending.