I'm not privy to what goes on behind the scenes but do wonder about the relevant experience of the management. I'd like to think things would be different if Alistair Welch was still at the helm.
Because traffic is falling does not mean the airport is not giving it 100% in trying to attract new business.
Success breeds success so airports that can show a track record of successful routes and airlines operating from their airport are more likely to attract more business than an airport that is having difficulties in keeping what it has already got. With that in mind I don't think Stobart Air has done Southend any favors.
Getting passengers to use existing services at a price that makes a profit to the airlines is key. While promoting the airport is so important adverts in the press costs money so budgets have to be spent wisely but a lot of money needs to be spent in the early years. This is money that the airport might not have but adverts like Southend is closer than you think or promoting Southend's rail link to London could pay dividends.
When easyjet first started to operate from Luton only, they used to have large weekly adverts in the travel sections of newspapers like the Daily Mail to get their brand recognized and it worked. In those days before easyjet arrived Luton had next to no scheduled services and was basically a charter airport with 20 years of zero growth but those easyjet adverts changed all of that forever