Short answer: it's a cluster. There's nothing cheap about aviation, add in that parts are one off and don't benefit from economies of scale and that $200,000 system is now an $800,000 system to manufacture. Oh, the FAA iterated requirements? Do it again. It failed a half million dollar test? Do it again. Safety analysis says it's no good? Do it again. Customer changed their mind? Do it again. Why didn't Boeing redo the system safety assessment after the MCAS change? That report alone likely cost millions to write. That sounds insane? Well that report is fed by hundreds of other reports, each fed by a few to several dozen other reports, each taking anywhere from 10 to 1000 man hours to write, all written by specialist engineers (like myself) all making $40-$100 an hour. That's just for the writing and analysis. A fire test on a relatively small part can cost upwards of $100k. Just the cowling, thrust reverser, and some of the tubing around the engines of the new G500 cost over a quarter billion.