This is the money quote you can use to argue this is actually corruption:

> When the 707 fell out of use in the United States, the trash can was no longer a “commercial” item, meaning that Boeing was not obligated to keep its price at previous levels

So now one can look why it cost "mere" $300 before, unless Boeing losing money back then the price hike may be shady behavior and then someone should change supplier asap.

Single source supplier tend to have incresible bargaining power. And 50k per E-3 propably isn't even worth mentioning for everyone involved. Peanuts, actually.

"The sum is low enough so it's not corruption" is also naive. Another side of the same coin