You have to have Boeing/Airbus approved hardware, which will come from one of the big boys in Aero Electronics (Garmin/Honeywell...) and cost megabucks due to a

You have to have Boeing/Airbus approved hardware, which will come from one of the big boys in Aero Electronics (Garmin/Honeywell...) and cost megabucks due to all the redundancy, testing, engineering. You have to have it approved by the airline, which requires all kinds of testing and red tape. You have to take the airplane out of service in order to install it, and train tech's to maintain and diagnose it, which means updated documentation. You have to train pilots on its functions, and how to use it properly, and all the implications of a malfunction in the hardware. Cost != airtime + cheap PCBS slapped in a dome on top of the airframe.