Also keep in mind that airlines book outstanding FF miles as a liability at miniscule levels compared to how FT'ers generally value them. The fact that you are earning a boatload of miles on a wacky routing isn't terribly relevant to them.

Their bigger concern with wacky routings would be if it prevents them from selling those seats to people who want to book the intermediate cities as standalone tickets. For example, if you're booked on BOS-ORD-LHR, and all BOS-ORD flights are oversold to the max but BOS-LHR (nonstop) has seats, I can see AA wanting to nudge you over to that nonstop flight so they can sell 1 more full-Y ticket to Chicago.

In today's model, it wouldn't cross their mind that you were mileage runner: they'd hopefully try and offer you a VDB tease to get you to give up your seat. If mileage running were widespread, they might change some rules - or at least reserve the right to move you over to "saner" routings at their discretion where it gets you to your destination ontime or earlier.