If this story is correct - it seems to have been leaked to The Times too so it's increasingly looking like it is - the only surprise is that it's being presented as the service chiefs making the case for F35B to DC. As the government's primary and over-riding focus is to reduce the deficit, making short-term decisions that reduce costs in the near future are understandable. What I don't understand is the military brass apparently making the case for the lesser military capability, rather than the government imposing it for cost reasons.
Probably doesn't make a jot of difference in the longer term as I expect the carriers to get shelved in SDR 2015, which would decouple the fighter decision from the carrier capability. It would also ease the time pressure on when we had to decide on F35 as we could maintain Typhoon/Tornado until at least 2020 when the SDR that year could review F35 options from a base of much greater knowledge of both capability and cost, as well as other options that might be available within a reasonable time-frame by then too.
It's a moot point whether opting for a fighter that could still get the chop from the US would be an embarrassment or a bonus to the UK government. If it's F35B or nothing, then a US cancellation would take the decision to scrap the carriers out of the government's hands. 'It's not our fault- the Americans made us do it'. Would they get away with that?
With 20/20 hindsight, the decision to go for new carriers and a completely new fighter at the same time was extremely unwise and fraught with risk to one or both components. What a complete and utter shambles. If the UK ends up with an effective military capability from this debacle, it will be despite of and not because of anything either the previous, current and probably the next government, has done or will do.