They promised a low cost way to give people assurance that their health care needs would be met. And since the HMOs' business plans were really an evolution of Medicare's prospective payment scheme, they began to bleed red ink in the accounting departments. Some closed their doors, and some adjusted to stay in business. So I do not feel you can offer a comparison of HMOs and insurers. I see them both as spots along the continuum of heath care in America.
Someone HAS to pay.
Without money, we could neither build health care facilities or staff them. There would be no research, and no hope for conquering ALS and other diseases. You cannot have your cake and eat it, too. And don't try to pander the socialized health care systems of other countries. I cannot envision any other answer.