The US has by far the most expensive healthcare in the world, and for all that expense, achieves outcomes comparable with the third world.
Negotiating with providers as a single payer massively shifts the dynamic by putting the negotiating power in the hands of the people representing patients, and allows a huge amount of bloat to be removed from the system - like the entire insurance industry.
Single payer will deliver huge savings, better healthcare, and better access. The people that lose are the grifters draining the system for profit.