Don't quote me, but something like $1000/month for employee +1 coverage. Of that, ~30% comes out of my paycheck and is tax deductible. Not to put too fine a point on it: $300/mo pretax is a steal. Even assuming the full cost would, IMHO, be reasonable. $12,000 sounds like a lot but I suspect that BCBS is doing more for me in real terms right now than the Federal government to which I hand over the equivalent of a mid-range Mercedes in income tax every year.
Even with the "high income" surcharge here for health-care, it's less than $1000 a year for an individual. Since it's deducted from your income along with regular payroll taxes, you don't even have to pay for dependents. They're covered under their own plan which is basically free until they start earning and paying deductions of their own.
In a start-up environment, $12,000 a year is not a lease on a Mercedes, it's the difference between your business floundering in obscurity and affording a few key networking trips, or the difference between living in a bedbug infested hellhole or having a decent apartment.
There are private insurance plans for exceptional circumstances, but these often over-lap with other policies to such a degree they're basically a luxury offered by companies to entice workers. The only real perk to them is the dental and optical coverage that isn't covered by the standard health-care system.
Are you comparing out-of-pocket costs for a single-payer health care system in Canada with the premiums for private health insurance in the US? Canada does spend less than the US on health care, but not ten times less; your taxes are making up a good chunk of that gap.
Factoring in that, the net cost might be subsidized by other taxes by at most ~$2000 more a year. Part of this is paid by the employer on behalf of the employee and isn't listed as a deduction. The rest is subsidies from the federal level of government.
The thing that makes this more affordable for people on limited incomes is how it's tiered, not a fixed price for everyone. If you're an entrepreneur barely making an income, you don't pay much.