Ryan is naturally aiming for the cattle class market, but I don't think it's going to work. Prices would have to be incredibly low - under £100 - to make people want to give up the small comforts they need on an extended flight.
It might be viable with the usual local subsidies scam, but what are the chances of that working now?
I don't take Air France because it's cheaper; I take it because I know I can take a flight two hours before or two hours later, or the next day instead of the one I booked. In the long run, we're all dead. John Maynard Keynes