"Whoops I made $600 from something that cost me $10"
I've written about this here some time ago - you don't pay for the soap dispenser or trash bin itself, you pay for the paperwork showing that it is safe to install this trash bin, soap dispenser or whatnot into this specific model of aircraft or spacecraft, and you pay for the paperwork that details the entire life of every tiny little piece used to manufacture that component. For flight-critical parts, IIRC that goes as far as to documenting the specific lot of the iron ore that was used to make the metal sheets, so in the event of something cropping up where something got fucked up in the mine or the smelter, you can recall every single part that could be affected. And there's lots of testing (and associated waste) at each part of the step.
Anything that goes into an airplane or spacecraft has ridiculous rules attached to it... rules that were literally written in blood. Aerospace is amongst the safest ways of transportation because of decades of crashes and learning from each and every single one.
Your average Home Depot soap dispenser has none of that, if it breaks it breaks.
What really makes me livid is that the same people who are in here now screeching about Boeing's misdeeds with no thought given to mitigating facts would instantly grasp the concept of paying for a paper trail and happily use it as justification to crucify some puddle jumping airline operator in Alaska who sourced unapproved stuff.
Feeling entitled to engage in cognitive dissonance like that when it benefits you plays a key role of so many problems in society these days, including shoddy work and overpriced soap dispensers at Boeing
That said, I still think $600 is absurd. The .mil probably already has a soap dispenser thats sufficient that Boeing could have made a mount for.