Originally Posted by eponymous_coward

Believe it or not, SEA-LAX-SJO is LONGER than SEA-DFW-SJO (thanks to the curvature of the earth) and of all the connecting points (PHX on US, DFW on AA, DEN on F9), would be the longest route.

I also find it pretty interesting that the Bay Area has no direct SJO service (you'd need to fly a UA codeshare down from SFO)- a much LARGER market than SEA, and this indicates to me that the demand you'd be able to get from SEA for LAX-SJO is pretty piddly. You'd really be needing demand from LAX to make this work, and I am not convinced it's there.