As another example, Des Moines to Dallas as discussed in this article. American has the only non-stop flights between those two cities, and any connection is going to add at least 2 hours to your travel time (based on a quick glance). On the other hand, nobody has a nonstop between Des Moines and Los Angeles, so American has no competitive advantage there and cannot command a huge price premium.
Or do you want them to lower the price of the Newark to Paris trip so that it sells out early and people who would have been willing to pay $1400 for that trip can't get to where they want to go?
They didn't, that means adding an extra flight might have been a lot more expensive. (due to, e.g. regulation limiting the number of planes in that route).
But it's probably not good business, since people get irritated by things like that and shop less.
Amazon.com has the lowest prices of them all. Its usually cheaper, and faster, for me to order books and gifts from the US site, pay international shipping and customs than it is to order from the local site, who may not get it for months if at all.