Just like how most public healthcare proposals in the US while technically raising taxes would end up leaving the individual with a much lower financial burden because of the ridiculous amounts of money Americans pay for healthcare and medication.
Let the government flex its muscles without artificial constraint, and watch how fast the market has to rein itself in to remain competitive.
The reason Medicare is loathed, is because Medicare has a mandate to not excessively spend, and it's pricing is actually determined by people with the public interest in mind first and foremost, as well as having its pricing accessible as a matter of public record instead of being hidden away in a locked filing cabinet somewhere.
The combination of those two factors are a powerful tool for shaping an industry away from "make as much money as possible while providing a service" to "provide as much service as possible while the money holds out".
It is a subtle, yet important difference.
Unlike with insurers where price gouging becomes viable.