I work for a health-insurance company, and my brother is a primary-care physician. As he tells it, my industry is responsible for the death of his. Insurance companies, he argues, have killed primary care by grinding down reimbursement and compelling doctors to see more and more patients just to make a living.

I sympathize with my brother, because I know that doctors' business with insurers isn't always easy. I'm also aware of the market's price sensitivity—and reimbursement paid to doctors comes from...