I guess the question is how much connecting traffic GCI generates on a daily basis. If there is a sufficient number of high yielding connecting pax (which I doubt), the airport should maybe push for focusing on LCY for all local London traffic and for using AMS or CDG instead of LGW for all connecting passengers. Would be a bit daft for passengers heading for final destinations in the UK and Ireland, but nowadays not a lot of them are served from LGW anyway (unless you count in self-built connections with the likes of Ryanair or easyjet) and some could be reached via LCY.