It sounds like you might be thinking something like: because these are taxes/fees that support particular services (like TSA, airport services, fuel, etc.), if we don't actually fly, the money doesn't need to be collected to pay the government/airport for those services. Kind of like how with certain hotels, if there is a resort fee or cleaning fee, you don't have to pay that if you make a reservation then don't actually show up, even if the room price is non-refundable.

You might be able to fight hard and get government taxes refunded, but those are a fraction of that $857.40. The overwhelming majority will be airline-imposed fuel surcharges, which are treated as part of the fare for refund purposes. According to United's refund policy: "Surcharges, including international and insurance surcharges filed as YQ or YR, will follow the refund rule of the fare. If the fare is non-refundable, the surcharges are also non-refundable."