Nellie
Your posts says to me you've never worked in airport development. As express flight says, it's a very long burn process and Southend is a 3rd tier London airport. Not only that, Southend isn't competing with London airports. It's competing across Europe.
An airline can chose where to base their aircraft and their choice isn't Southend or stansted, it's London or Liverpool, or Paris or Milan or Rome.
For Southend to win it has to be prove that the risk is worth it, and the risk is huge. The cost of operating 1 737 for a year is something like £10m - massive numbers.
Southend is doing well, yes it's in a period of consolidation but it will come out of it and grow. All new airports go trough the same.
I can see how it may appear frustrating that stansted or Luton get growth seemingly at the expense of Southend but you don't know how long Luton or stn have been working on these deals and it will have been years.
I now work for an airline and see the airline operation on a daily basis but prior I worked doing airport development and it's hard, very hard.
Be patient ...