It's been proven to be less expensive in other first world nations. When you eliminate all of the paper pushers who have nothing to do with actually delivering health care to people--the insurance companies, medical billings people, insurance brokers, company benefits plan managers, etc., you can save a whole lot of money and enjoy increased efficiency.
It's been shown that the U.S. is currently spending 17% of its GDP on health care while leaving tens of millions of Americans uninsured or under-insured with the rest living in sheer terror of losing their jobs and health insurance while having hundreds of thousands of medical bankruptcies and businesses and an economy burdened by insurance issues.
In contrast, other nations spend a smaller percentage of their GDP on health care while having 100% coverage, zero medical bankruptcies, and businesses and economies that aren't burdened by insurance concerns.
How do you explain that? Basically, by removing all of the inefficiency inherent in our type of system, they're able to do all of that for a smaller percentage of GDP. Why can't the U.S. do the same?
Anyone concerned about this issue should watch this excellent PBS program that looks at other nation's health systems and how they do it:
http://www.pbs.org/wgbh/pages/frontline/sickaroundtheworld/