Any argument I can make here in text would only serve to make me appear to be against individuals having access to healthcare... and that is not a winnable argument (nobody looks good when they make any stand against a social issue).
The numbers I'm referring can be wide in scope. For example, the economics of providing such a socialized healthcare system are difficult to surmise, however there is a lot of data which may indicate it's not economical at a federal level (maybe at a state level, sure).
Also the numbers of citizens with interest in such a program is low, to date only 8 million US citizens have signed up for the federal/state exchanges, out of around 360 million US citizens; about 2% of the country. Only 16 of 50 states have built local Exchanges, the rest deferring to the Federal Exchange for various reasons including but not limited to the economics behind building such a portal, maintainability of such a portal, and some flat-out refused out of political, moral, or economical principal.
The current program provides almost none of the goals it set out to accomplish.
With the current program, it is still very possible to get a horrible disease such as Cancer, and leave the hospital with $60K+ in bills. The current program made almost no changes to the Pharmaceutical industry, which charges in excess of $300 per pill for some treatments when the cost-to-manufacture is known to be significant multiples less. The current program does not "provide" healthcare to anyone, it merely made it illegal to not have healthcare (with fines imposed if you refuse). The current program provides a way to get access to healthcare (via the government) if you have no other access, however it's arguably not affordable at all (the current program is estimated to cost a family of 4 around $4,000 USD per year -- and it's likely a family of 4 without healthcare might not have it because they could not afford it, nor can afford an extra $4,000 a year... but now it's illegal to not afford it).
I digress. This debate can easily turn into a flame war, and is off-topic for a thread discussing a city implementing municipal high-speed internet.