LEEDS APPROACH
Not sure what your agenda is here. Whatever it is, as others have already suggested, the logic is flawed.
Passengers "lost" by EMA will be picked up, generally, by one of three airports. In order, these will be BHX (because of it's proximity and range of destinations), LBA, and finally, if the destination is available, Doncaster. None of these are MAG airports, so IF a strategy such as you are suggesting were in play, MAG would be cutting off their corporate nose to spite their face.
There has been over capacity on some bucket and spade routes at EMA for a while. The loss of Monarch, combined with the growth of capacity on some routes at BHX / LBA will have redressed the balance. Whilst airlines like the discounts that some airports offer to attract them, if they can't put adequate bums on seats at the right yield something will give, and in the summer just gone, this appears to have happened. I see it as short term blip, not a long term decline.
Anyway, please look at EMA in the round. There is more to EMA than self loading freight. Pure freight is a real success story here, and whilst I have no idea what the split is, I would guess that the cargo sector provides something close to half the revenue for EMA, and is probably one of the chief drivers for MAG investing in EMA.
By the way - as has already been mentioned, why is this thread being opened, when there is / was a perfectly adequate existing thread, which to the best of my knowledge hasn't been shut down?