You keep saying this, but when asked what mandatory services are causing premiums to go through the roof you haven't offered much.
Using your analogy, when you take your car in and the mechanic says you need to do "x" on your car what is your response? Mine is usually a combinations of questions like why, how long does it take, what's involved, and how much?
Insurance companies realize that you get the same response in a conversation between a Doctor and a patient. I would argue that most patients are likely to decline or postpone a recommended care plan if the answers aren't low impact. Point being, if the doctor wants you to do something, the insurance company wants you to do it too. So they write plans to cover these "non-essential" things because catching things early in medicine is the best cost savings tool insurers have.
Your root issue is that what you consider non-essential, is only non-essential to you right now. Insurance policies, any insurance, does not care to cover you at an individual level. It's profits are based on pools of policy holders. This is not an ACA consequence, it's actually the free market working as intended.