Can you define further, GSLOC?
... passengers are willing to make to get from A to B depending on underlying factors like total trip distance, costs, etc.
I'm not in the business, just a long term user of it (month short of 48 years since my first commercial flght), so this is my guess: If any research exists it will be out of date.
It used to be the case that you could make many hops to save money but numerous countries now charge a panoply of taxes (landing, departing or whatever they can think of, not to mention Visas) that the cost of hopping is now more expensive.
I recall a few years ago, looking at making a series of hops with some connections and some stopovers for UK/Oz and the costs quickly spiralled.
Secondly: Time. Those that have the time to make such a route are probably few and far between.
But that's just a 'from the hip thought'. For myself? Being older, I certainly want to cut down on the connections! If I was 18, I probably wouldn't mind -
if it would save money.