In Europe, some large programs (like “free” healthcare and college”) appear to work for some countries and are a complete disaster for other nations. In many southern European nations, citizens look on state provided healthcare with horror, and make every effort to insure that they don’t have to depend on that system.
American progressives are strangely incurious about what makes some systems work and other systems crash and burn. In many cases, the explanation is cultural and institutional. 
(As it happens, Scandinavians had a well-established culture of hard work and self reliance and social cohesion, which is what made the establishment of a large welfare state even possible. When the Scandinavians began their ambitious welfare programs, it was a point of honor among many to NOT USE IT. This attitude has been eroded over time).
The Scandinavian models also have had better success rates because they have focused on maintaining a VERY FREE business environment, with corporate taxes LOWER than are found in the US, and limits placed on unions (a practice that would be abhorrent to the average American progressive).
When large government programs are established in the U.S., they 
quickly become bloated, inefficient and corrupt. The government is currently $21 trillion in debt.
Why not demonstrate that they can do the job they already have before being given control of the healthcare industry (an estimated 1/5 of the economy)?
Opponents of the progressive welfare state believe that considerable damage could be done to the American system (which has always been a powerhouse of innovation and expertise), and many people could be hurt.
