With respect - it's not that simple
Mrs FFMAN and myself along with 4 friends were booked on a MON flight in November. After the sad demise of MON, we looked at alternatives. The best was Easyjet at £526 pp against the £180 pp from MON. We have all decided to put it down to experience and not bother this time.
It's not so much the money - it's the principle.
So no doubt some will fly other airlines but many won't. MON was offering very good deals (we now know why) that were incentives to travel where perhaps people might not have bothered previously.
Plenty won't bother now