As Professor Glenn Reynolds says, “All is proceeding as I have foreseen“.

Nearly 4 million young people will be much better off financially if they refuse to buy an ObamaCare insurance policy and instead pay the fine for going without coverage next year, according to a study released Thursday by the National Center for Public Policy Research.

The study found that 3.7 million childless single people age 18-34 would save at least $500 if they didn’t buy insurance and instead paid the tax penalty next year. Of those, more than 3 million would save at least $1,000.

That’s despite the heavy taxpayer subsidies many of these young people would be eligible to get. The ObamaCare insurance exchanges provide tax credits to offset the cost of insurance to those with incomes up to 400% of the poverty rate. The NCPPR study used Census data on income and insurance coverage in this age group, along with the Kaiser Family Foundation’s subsidy calculator to arrive at its results.

These findings are troubling because they point to what could be a fatal flaw of ObamaCare if the administration can’t convince enough of these “young invincibles” to buy coverage.

“This age group must buy insurance in the exchanges to cross-subsidize people who are older and sicker,” explained David Hogberg, a policy analyst at the conservative National Center. “Without them, the exchange will enter a ‘death spiral’ where only the older and sicker participate and the price of premiums increases precipitously.”

Most of those who stand to gain by not buying ObamaCare insurance are currently uninsured today, said Hogberg, who used to work for Investor’s Business Daily. “Getting these people to shell out $500 or $1,000 of their own after-tax income is going to be a difficult task, to say the least,” he noted.

Hogberg cites the example of an uninsured 22-year-old earning $18,100 a year. Under ObamaCare, she’d be eligible for $1,329 in subsidies. But she would likely save $117 if she paid the fine and remained uninsured. “I could easily use that money for groceries or transportation,” she’s quoted as saying.