Thomsonfly are facing the same problem as all the other package tour operators. The bog-standard package holiday market is shrinking. People are either booking themselves on the internet, and searching for their flights, or are looking for something more from their holiday than they currently get and are venturing further afield.
The effect will vary from airport to airport. You need package tour holiday makers to fill most of the plane, if they are not there you pull the flight. It is nonsense to suggest that because one airport is losing out so should another in an adjacent geographical area. Depends on the availability of other flights, holidays etc.
There are going to be casualties. Lets hope they are few in size and number.