Unwell_Raptor said it back on the first page, I think - would pax be able to put up with no food etc and no frills service for 7 hours plus? Or do you collect your sarnies and your lunch box at the gate?
Squeezy's business model (and Ryan's for that matter) just doesn't stand up for long haul ops, cos you can't keep the costs down - especially if you want a developed network, cos you'd have to have a hub and spoke operation, and it's that which is costing the big boys money. You'd need massive LFs for a successful point to point service, and I just couldn't see them consistently getting that. With the "real" airlines offering 200 quid returns to the States, there's not really a lot of market for the LCAs to eat into.
Personally, if I'd flown to the States with a LCA (or any other airline, for that matter) and my return flight had gone tech, and the airline refused to rebook me or put me up in a hotel until they could get me back, I wouldn't be flying with them again!