Originally Posted by
LarkSFO
Intentionally or not, you have answered the question more accurately than anyone else in this thread.
The only qualifier I would add: Sometimes, a route is deemed 'strategic', in which case UA will sacrifice yield to maintain their dominant position.
Clearly, IAD-FLL/MIA are not strategic.
Also, looking at the supposed market for a product is only one part of the analysis. You also have to look at who is competing to sell that product.