Insurance companies cannot ration health care. They can say what they will pay for under their contract with me or my employer (and sometimes they do cheat), but they cannot forbid me from seaking other care. Government on the other hand can make it illegal for me to seek and for my doctor to give me treatment we both agree is best for me. I'm waiting for back alley chemotherapy by those seeking care made illegal (or at least delayed for months or years) by Obamacare.
That's not what will happen. People will discover the joys of gaming the socialized medical system, just as others in socialized countries have done.
This will involve (not in any particular order)
Bribes (your doctor, hospital, druggist, politician)
Medical tourism (running to Mexico, or other places to get things done)
Mafia (physical threats against doctors, politicians, etc. to get things done)
Emmigration (going to live in other countries who will provide services for family members who get sick)