It tells me you have no idea of your facts! Lets look at it in a little more detail maybe I an help you out
1) When Aer Arran operated it Flybe were also flying into LGW on four rations a day so there were too many seats.
2) When VLM operated it they did do alongside Euromanx and Flybe were still flying into LGW. Incidentally VLM only ever used it to park the plane during the day as it was more cost effective than holding it at LCY.
3) Flybe did it years ago it was a Belfast service that stopped at IOM. Again it was up against 4 rotations of LGW so too many seats.
4) Eastern operated on behalf of BACF again there were two Easyjet rotatios at 156 seats a go for it to go against.
5) Loganair operated it on behalf of BACF again there were two Easyjet rotations.
Also as I pointed out in an earlier post if you had bothered to read it LCY was running three rotations whereas I suggest only two are needed ( I think this was to utilise the plane throughout the day as the BA agreement meant they could not serve other markets). So in every scenario you have provided there were about 350-450 seats going into the London market causing an oversupply. On the model I have suggested there would be about 250-300 seats which I would suggest is about right for the market.