At a gathering in Burlington, Vermont, convened by the Sanders Institute, with support from National Nurses United, I spoke about the perils of mixing Medicare with commercial insurance. We need improved Medicare for all, one single federally administered health plan that meets everyone’s needs.

To maximize profits, commercial health insurers, including Medicare Advantage plans, almost have to be in a race to the bottom, steering clear of delivering good affordable care to people who most need care. They don’t compete to deliver better care at lower cost for people with costly needs and never will. It’s not in their financial interest.

Think about it. When was the last time you heard Aetna, or UnitedHealth boast about its great cancer or stroke care or say “Join us if you have heart disease?”

Commercial health insurers too often design their networks so that they don’t include the top cancer center or other centers of excellence in a community. They want to keep people with cancer and other costly conditions from signing up with them. Have you ever heard of a health plan that says if you need costly care, you can use top doctors and hospitals with low costs? That’s the one we all want. That’s Medicare for all. You can’t get that from a commercial health plan.

Here’s why. If a group of people got together to offer the best commercial health insurance, with a robust network of the best hospitals and doctors, we’d be out of business before we opened our doors. Everyone needing costly care would join. We couldn’t spread costs across healthy and sick. And, we couldn’t afford to deliver needed care. And, that, in a nutshell is why commercial health insurers will never meet our needs.