Probably linked to what the networks they used rather than SuC themselves, but I agree with the point.
The model was always difficult unless you were the defacto standard and everyone needed to be on it. If they are cheaper than the network, who pays the difference, and more expensve and why would anyone use them more than just occassionally? The "joinbonnet" website didn't actually work either unless you were on a mobile phone and downloaded the app.
I think it would work better if the networks themselves joined together and pooled their capability, albeit that might give the competition police a headache
Sad to say it but I give them 6 months unless something magical happens.