It's not pre-paid care. It's not a discount plan. Really, it's a gamble.
Health insurance is ridiculously expensive because health care can become ridiculously expensive. Sure, you're healthy and accident-free, but the costs of a traumatic accident or long-term illness could easily reach 6, possibly even 7 figures in the long term. That's what your insurance is paying for.
For any type of insurance to work, you need people that aren't making claims to fund the people that are making claims. If you take the attitude of "Why should my premiums pay for someone else's care?", then really there's no reason to even get insurance. Your insurance is costing $25K/year, because statistically, the average family has at least $20K in healthcare costs per year (Assuming the insurance company is satisfying the ACA requirement of 80% of premiums must go to paying for care).
Your $25K/year in premiums is a bet that you won't need some $Y to pay for healthcare, where $Y >>> $25K. Most of the time, you're losing that bet, and the insurer is making $25K off of you. But if you ever find yourself in a world of hurt (quite literally), you'll be glad you made the bet.