I don't agree. Remember there is a new owner and they are going to be making some changes, attracting more airlines is one of them! BAA never made a real effort at Stansted since the economic downturn, MAG will and are doing more so and I think a lot of the carriers that were orginally at Stansted that have gone to Gatwick and Luton (with the exception of Norwgain) could be quite realistically tempted back to Stansted if they get a price and deal that is right.
It only takes a look round Gatwick to see what new ownership has done and there's no reason really why Stansted can't do the same. Yes it may have slightly longer rail times but it has better motorway access and slightly faster links by road to Central London and Stansted has the benefit of being a modern and good quality airport which doesn't suffer from major flight delays and capacity constraints like Heathrow and Gatwick. That along with an owner who can offer competitive deals to airlines will in time attract more carriers in the future.