The owners don't want or need it to become a long haul airport.
I wouldnt say you are wrong that they dont need it to become one but there would be no reason they wouldnt "want" to become one. Airports like being connected to everywhere, It is prestigious.
I would also say that in the long term they can achieve long haul flights without touching the runway length. Airliner capabilities will continue to improve. I could be wrong but if it was financially viable and worth it a 787 could use LTN without much if any restrictions for flights already couldnt they?