No airline can afford to take risks. This is why airlines go out of business.
BOH is completely different to CWL, the area is much more wealthy so the odd flight to GVA in the winter works. FR can't even make BOH work, with flights stopping for three months a year.
Let us look at EZY from DSA. By your logic EZY from DSA should work with MAN just up to road. It didn't even last a year.
