The assumption that Ryanair will win a price war doesn't sound too far fetched to me. It has larger cash reserves than any of the competitors and the lowest operating costs in the business, which puts Ryanair at a significant advantage over the rest.
As far as I'm concerned, the so called low cost airlines that are neither here nor there, eg Hapag Lloyd Express, flyBE, bmiBaby and German Wings are most likely to go under. Although they have substantial backing from their parent companies, they will not sit out losses in the long term, similarly to the Go situation with BA. If you remember, the only market that Go was breaking into was BA's own, similarly to German Wings and Lufthansa.