According to the Congressional Budget Office:
The budget office estimated that about 6 million people would sign up for the public option in 2019, when the House bill is fully phased in. That represents about 2 percent of a total of 282 million Americans under age 65. (Older people are covered through Medicare.)
The overwhelming majority of the population would remain in private health insurance plans sponsored by employers. Others, mainly low-income people, would be covered through an expanded Medicaid program.
Most people won't have access to the public option plan:
Under the House bill, it would be offered through new insurance exchanges open only to those who buy coverage on their own or work for small companies. Yet even within that pool of 30 million people, only 1-in-5 would take the public option.
The public option may not turn out to be cheaper:
The budget office said "a less healthy pool of enrollees" would probably be attracted to the public option, drawn by the prospect of looser rules on access to specialists and medical services.
As a result, premiums in the public plan would be higher than the average for private plans. That could nudge healthy middle-class workers and their families to sign up for private plans.
Insurance companies don't care about the CBO numbers. They still oppose the public option:
While a government plan might start out modestly, insurers fear that Congress could change the rules later, opening it up to all people and setting take-it-or-leave payments for hospitals and medical providers, instead of negotiating, as the House bill calls for.