Seat62K
... with the return sector Dorval-Pittsburgh-Charlotte-Gatwick.
My guess is that was in the time when Hub-and-Spoke was the Big Idea? The majors were offering good prices if you were prepared to multi-hop, so that they filled up empty seats and made the load factors look good.
Another example, UK to South Africa, was usually MUCH cheaper on an indirect LHR~AMS/CDG/FRA/MUC/MAD/~JNB but not now.
From recent investigations of getting UK to Canada (and UK to other places) I can see that the indirect routings are much the same price and, often more expensive. The Hubs-and-Spokes have been greatly reduced and the indirects with a single change have risen in price to the point where they are a bit cheaper than the direct but not a whole lot cheaper.
Usual caveat, what each pax considers 'cheap' or 'cheaper' is their own and there are going to be many examples of cheap routing too. Overall ... it is a different world and the next two years will make it the more so.