Why? It just raises the bar for the unions: negociating co-pay, dental plan... Plenty of healthcare things will not be covered by Medicare. Unions will negociate about this.
"All Americans would have coverage for comprehensive health care services, including hospital stays; emergency room visits; doctor visits; substance use disorder treatment; dental, vision, and mental health services; long-term care; and reproductive health care. Depending upon income, prescription drug cost sharing would be capped at $200 annually." -- https://www.webmd.com/health-insurance/news/20191120/medicar...
Obviously, there might be some edge cases. This is where private insurers could still fill a role. I can't imagine that extra/supplemental private insurance could be too expensive, if it had to compete against a unified 350 million+ person insurance pool.
Edit: It is worth noting that the US is pretty unique when it comes to the separated dental insurance coverage plans and main health insurance plans.
That's actually great! But what will the actual terms and conditions be? Some existing examples: a maximum number of psych visits, (medical) dental work up to xxx$ per year (if you had a checkup last year), limited coverage for experimental treatments for like cancer.
The US is not (wont be) the only one which seperates dental (as in infections, teeth removal) from orthodontic like braces and fake teeth.
Would nationalized healthcare cover orthodontics? I could see an awful lot of union members being interested in supplemental family dental from employers.
"All Americans would have coverage for comprehensive health care services, including hospital stays; emergency room visits; doctor visits; substance use disorder treatment; dental, vision, and mental health services; long-term care; and reproductive health care. Depending upon income, prescription drug cost sharing would be capped at $200 annually." -- https://www.webmd.com/health-insurance/news/20191120/medicar...
