I think their coach operations are in a precarious position too.
In many areas they can only run services that aren't journey time sensitive unless there's a really huge market (like Cambridge to London) as getting into London and certain other cities by road just takes soooo much longer than by rail that only people who really really want a competitive fare would use them. This immediately sets them on the back foot for trying to actually make money out the route, and is a situation that's getting worse every month that goes past. (Why would you use National Express from Essex to London?)
In addition, the strengths of being a near virtual operator are also weaknesses. Contractors could decide to try things out for themselves, to operate for a competing virtual operator that offered better terms, or even to unintentionally do stupid things and give them a bad reputation, ...
They are already coming against meaningful competition from Megabus, and First Greyhound are threatening to join in the party.
In recent years they have benefited from and expanded rapidly in an area that had the potential to be a huge strength for them; airport services. Not only are there are massively more people travelling to and from airports, but low cost airlines have ensured that these people are probably cost conscious, very likely arriving at the cheaper airports least well served by trains, and could even be arriving at antisocial times. In addition, the wide catchment area of an airport means that these people will be coming and going in all different directions 24 hours a day, in ways that it would be hard for a rail service to compete against.
An added bonus is that they can make these services premium services; people are not just going to airports whenever it's cheap; if they need to get there at 6am and leave at 2am that's what they need to do, and they'll pay for the privilege.
However with air passenger numbers now heading the other direction, this market may shrink. It would also not take much of a change in business model and direction for the likes of Megabus or First to start putting up some decent competition against airport services (though to compete really effectively both would need to change their strategy of trying to get advance bookings for particular services).
There's also constant rumblings that rail operators might threaten to get their act together and run a few more airport services.
Additionally, more people going to airports may be a blessing in disguise, as the low costs airlines these people are flying on must have caused Eurolines a lot of pain.
One think that I think is a potential opportunity for National Express is better local marketing. We all know who National Express are and what they do, and we all know that they probably run a bus from a mediumish sized town near us to London, or to an airport.
But they also run lots of other services that are harder to find out about. Because of the way their website and works and leaflets are set out you can't find out what routes they run good services on without searching for every journey you might make and usually being disappointed by a daft suggestion. If I pick up the all towns and cities leaflet, 80% of the journeys suggested in it will probably be stupid or ridiculously slow; I am not going to wait in Birmingham for 2 hours in the middle of the night in order to get anywhere!
As an example, I live in Cambridge. If I wasn't into transport then all I'd have noticed is that there are lots of buses to London and London airports; and if I pick up a leaflet these are the ones I'll see. Because they run at rush hour I might have also noticed buses that say Clacton or King's Lynn on them.
But when it actually comes to looking at the board on the bus stop and finding out about return journeys from their website; the surprise destination National Express run a good service at useful times and with not bad journey times and a competitive fare to is (or was) Nottingham. I'd have never known that. I always took the train there because I thought it was the only way.