Approved expenses being something the insurance company is aware of, has set a cost to, and has qualified in your plan. I think you'd have to have a pretty lousy health insurance plan to not have as much antivenom as prescribed by a doctor covered.
I also don't see how $40,000 is expensive, given what it takes to make and store anti-venom. There are conventional made bio-pharmaceuticals which can cost more than that per dose.
Just because your doctor prescribes something doesn't mean your insurance will cover it. The national standard was lower to Medicare and that's what most insurance companies are lowering their coverage too to save money. They are pretty much required to do anything they can to lower costs so the can offer cheaper insurance. Not covering as much is the easiest way to do that. Test strips for diabetics are approved for up to 3 times a day and no more. If your doctor prescribes more than that, you can get it, but you have to pay 100% of the cost under any plan that is already conforming to federal law. As you said, what is qualified in your plan. If you only 3 test strips a day are qualified, the rest is out of pocket. I was prescribed 9, my health insurance covers 80% of 3, and I can only afford to pay 100% of 3 more, so I only get 6. When you live paycheck to paycheck, what your doctor prescribes doesn't matter. What your insurance allows does.
Also, agree with you on the $40,000. If it cost $40,000 to make and you don't have insurance, $40,000 should be your bill. Question is, how much of that price is the real price and how much is just markup for profits.