_aax1
Surely the whole idea of Stobart running their own services to some non-bucket and spade destinations is an attempt to prove your premise wrong. I tend to agree with you regarding CGN where I feel that double-daily is required to prove its viability into SEN, although I don't expect the route to be operated, as you seem to suggest, by "a small aircraft" thus limiting its economics.
It will be interesting to see if destinations such as BUD, FSC, LYS, MXP, PRG and VIE prove successful while DBV, REU and ZAD are new sunshine destinations not tried from SEN before.
On the basis that "the competition that exists on all routes are just too high" one would not have expected SEN-AMS to be able to support a 3 x daily service (this being seasonally adjusted downwards simply due to the desire to maximise other routes' potential, SEN being only a three-aircraft base). Competition on any LON route signifies high demand so is not necessarily a defeating factor.
So let's wait and see what loads are like in the first three months, with some attempt to also assess yields, before declaring the initiative to have been a failure before it has even started.