Sawyer said that e-mails ABC News had received argued that "the Mayo Clinic is exactly the point," indicating that private companies are solving this problem, and raising the question as to why the government needs to get involved.
"And, unfortunately, government, whether you like it or not, is going to already be involved," Obama said, citing Medicare and Medicaid.
One questioner -- Marisa Milton, vice president of health care policy for the HR Policy Association, a public policy advocate for human resource executives -- said that "other industrialized nations provide coverage for all their residents" with "high quality care" without spending more money.
"A lot of those countries employ a different system than we do," the president said. "Almost all of them have what would be considered a single-payer system in which the government operates what is essentially a Medicare for all."
The president said he didn't think it wise to attempt to "completely change our system root and branch" since health care is one-sixth of the U.S. economy. It "would be hugely disruptive," he said, arguing that citizens would be forced to change their doctors and insurance plans "in a way I'm not prepared to go."
End-of-life issues were raised as well; right now it is estimated that nearly 30 percent of Medicare's annual $327 billion budget is spent on patients in their final year of life.
Jane Sturm told the story of her nearly 100-year-old mother, who was originally denied a pacemaker because of her age. She eventually got one, but only after seeking out another doctor.
"Outside the medical criteria," Sturm asked, "is there a consideration that can be given for a certain spirit ... and quality of life?"
"I don't think that we can make judgments based on peoples' spirit," Obama said. "That would be a pretty subjective decision to be making. I think we have to have rules that say that we are going to provide good, quality care for all people.
"We're not going to solve every single one of these very difficult decisions at end of life," he said. "Ultimately that's going to be between physicians and patients."
The president said, "About a third of the costs will come from new revenue," and pushed his proposal to raise taxes on those making more than $200,000 annually through a change in the itemized deduction in the tax code.
Gail Wilensky, a senior fellow at Project HOPE who ran Medicare during the administration of President George H.W. Bush, pushed the president for more specifics on how he expects to pay for the plan.
"This is not an easy problem," the president acknowledged. "And it's especially not an easy problem when the economy is going through a difficult phase."
But the president suggested the stars were aligning for reform, citing efforts being made such as the pharmaceutical industry's recent pledge to help defray the costs of prescription drugs for seniors, and argued that now was the time for reform.
"We have to have the courage and the willingness to cooperate and compromise in order to make this happen," the president said. "And if we do, it's not going to be a completely smooth ride, there's going to be times over the next several months where we think health care is dead, it's not going to happen but if we keep our eye on the prize ... then I'm absolutely convinced that we can get it done this time."