A jar is a mostly once off cost, you build the jar making machine and it works until it breaks. While AirPods are under constant innovation. So the initial cost has to be repaid fast.
I wouldn’t know where to begin with research and engineering, since all their products benefit from audio research and testing, iCloud, device inter-connectivity, etc. AirPods wouldn’t be any good without years of prior work on iOS. But they reportedly assign development costs roughly equal to manufacturing costs, which would put them at $60 and $100 of margin. This would make them contribute more to Apple’s target margin than the average product. This value is possible because of the state of the market, for whatever reason.
I want to push back on that because the no name brands are cost cutting by just repackaging cheap off the shelf bluetooth boards, speakers, and batteries. They do make for a perfecty serviceable pair of earbuds but they aren’t what you should be price comparing to which is other manufacturers making actual comparable products from Sony, Google, Bose, Beats, Samsung which range from $100-300 but mostly hover around $200. Go with a 50% markup from wholesale to retail and you’re looking at probably $100-120 real manufacturing cost.
Apple also negotiates better margins on wholesale than 50%. They wouldn’t make much money on $170 AirPods otherwise assigning $60-70 research and manufacturing cost, let alone $100.
If you add the cost of the tooling and manufacturing line, and NRE costs, maybe $25 a pair.