DarkStar
There was never any realistic prospect of moving the church, it being a listed building and due to the vociferous opposition of its congregation, so the economics of doing so were thus never tested.
Far from being in "rapid decline" turboprop aircraft in the 30 to 80 seat category have never been more popular with VLM recently announcing they are not replacing their large F50 fleet and Flybe stating that it was largely through the excellent economics of the Q400 that they had successfully survived the oil price increases of the past year. In fact, it always surprises me to see so many turboprops at the regional airports that I visit.
The Evening Echo is nowadays very supportive of SEN, something which was unheard of just a few years ago, so there is certainly no excuse for residents not being aware of the situation and I don't believe that they are generally unaware that there is the real prospect of a range of destinations being offered next year.
You say "people look to STN and LGW", well of course they do at the moment - no point at looking at SEN when it doesn't offer any flights is there? I think you are wrong in suggesting that Joe Public would prefer to travel to STN, LTN or LGW to catch his B737/A319 (with all the hassle involved) rather than flying on a Q400 to PMI or ALC. I don't think the SEN-JER route has suffered through not offering jet equipment and the speed of the Q400 means there is very little difference in block times on even a 2.5 hour sector. LCY also certainly doesn't seem to put people off by offering largely turboprop routes.
If SEN is to remain a "dead duck" unless it gets "a decent runway", then a dead duck it will remain as there is no prospect of extending the Runway Strip (it's the 300 m wide Strip which is impossible to achieve, not just the runway itself) beyond the amount I suggested in an earlier post - not while the church remains at one end and the railway line at the other. So, it will be by use of aircraft such as the Q400/ATR42 & 72 etc., plus perhaps the F70/A318 that SEN will either sink or swim. Don't be under any illusions either that SEN will survive by just serving as a maintenance and storage airfield - at the end of the day that will not produce sufficient revenue for survival.