If we want a government option for healthcare, why not just expand medicare and allow anyone to join?

Because that would make too much sense. AND it would not grow the government enough to satisfy the current powers-that-be.

The healthcare plan just passed by 220-215 in the House on Saturday would create  lots of new govenment entities - in fact 111.

New Federal Bureaucracies Created in Pelosi Health Care Bill - GOP.gov

Here's #1. "Retiree Reserve Trust Fund (Section 111d, page 61).

And #111. "Committee for the establishment of the Native American Health and Wellness Foundation (section 3103. page 1968).

Hit the link for the other 109 new agencies/committees/organizations/Device registries/etc, etc, etc.

Could it be, is it just possible, that the rationale for creating an all new entity, rather than simply expanding the current (medicare) entity, has very little to do with healthcare. BUT very much to do with more government employees, beholden to, and tending to vote for, the Party (Democrats) who created and keeps them in their jobs?

Hah!