I thought it was stupid to offer free Wi-Fi for all, as it would (and no doubt did) impact on the quality of service. They could try and block certain services or ports, which I think they also did, but then you've got a sub-standard service. I've used it on EC and it can be very good one minute, then useless the next.
When you have limited bandwidth and a number of other technical issues, especially using a service that is not as advanced as that used on other lines (it's older and works in a different way), then it does make me wonder why National Express ever opted to make it free. I guess it was to give them an edge, but it did impact on the service without a doubt.
Yes, the system they have is probably all paid for (besides the ongoing data charges) so it can be used as a loss-leader, but is there any reason to if the extra revenue from charging can be used to subsidise something else (like ticket prices)? Also, where does the money come to upgrade the hardware in the future?
The other systems won't go free as they were installed free of charge by the provider, so going free would mean no revenue at all. Indeed, if everything was to be free then there's very little incentive to fit Wi-Fi on future trains. It might be worth doing so either for first class only (if it sells more first class tickets), but is it good to do it because everyone else is doing it, when I doubt anyone wants to do it in the first place. Wasn't National Express the first to do it and effectively screw it up for everyone else?
More and more people are quite happy to use their own 3G (and then 4G in the future) and get much faster speeds, without any restrictions.
All I will say is that the charges seem too high, but it might be the case that EC wants to keep prices high to put people off and reserve bandwidth for first class users.