We gave just about the same answer when asked why Trane and Lennox ACs are so expensive.
There are several reasons.
Quality: Carrier Infinity and Performance Series air conditioners are better than most. Service records showing fewer repair issues demonstrate their quality. You get what you pay for.
Carrier-certified Installers: To install Carrier equipment, you have to get special training from Carrier. This isn’t foolproof, but does make it more likely the AC (or heat pump, furnace, boiler, etc.) will be correctly installed – and that it will be less subject to breaking down.
It’s a Carrier – It must be good: Carrier enjoys an excellent reputation. Many homeowners are willing to pay more for a Carrier because they’ve heard good things about the brand.
Marketing: Carrier advertises more than most brands. That raises equipment costs.