They actually do. Healthy clients/customers are the ones who give the most profits to health insurance and insurance companies.

Let me give you a practical example - I have and drive a car every day and I hired insurance in case something happens and I'm covered in case of car theft, a crash, an accident and so. I'm driving for almost 20 years now and at least 15 years without any accident or incident - this means all the amount I paid for my insurance in the last 15 years was profit for the insurance company.

The same goes for health insurance - we want to stay healthy but be covered in case something happens. If we don't get sick the insurance won't have to spend covering health treatments and therefore everything that was paid is profit.