There wouldn’t be a for-profit middleman taking billions out of the system for themselves yearly.
Critics point out that government-run healthcare would be less efficient and would also have to draw the line in approving/denying care somewhere too, but I can only imagine that it would pale in comparison to the insurance companies who have a profit-motive to screw you over.
Supporting this assumption is the fact that Americans already spend way more on healthcare than other countries, even those that already have universal:
So, basically we’re all overspending solely to make insurance companies rich.