Very few units over which to amortize everything. I can't recall the exact numbers, but there were years in which (I believe it was) Continental shipped 80,000

Very few units over which to amortize everything. I can't recall the exact numbers, but there were years in which (I believe it was) Continental shipped 80,000 small aircraft engines, and a decade or two later, they were down to shipping ~3,000/year.