Volume
I toured a small local aircraft manufacturer lately. They have something like 98 workers to produce 5 planes a month. It is no wonder they cost over 150K each. Each workers earns their wage plus health care, labor and industries insurance, retirement, ect... Then you have overhead like paying for the cost of the building and liability insurance.
If they could spread all those costs out over 500 planes a month then the price could be cut significantly. GA is fading and the resulting low volumes are finishing the job. Send them all to Mexico or China where costs are low.
Skyhigh