check the age of the moulds. pretty sure the S2 and S3 are newer moulds than the P2. The P2, while a fine bike, is a pretty old mould. The S3, is obivously the newest mould, being a 2010 year model.
when a manufacturer invests in a mould, he needs to sell his bike at a price point where he can cover the cost of producing the mould , R and D, as well as raw materials / paying staff etc. as more and more P2s have been sold over the years the cost of the mould and R and D costs have obviously been paid off and cervelo can obviously offer it at a lower price point and still make a profit. do note the market the P2 is targeted at- it is their ‘entry level’ offering so obviously being cheaper helps. its like how new technology gets cheaper over time.
also, like someone else said - supply and demand. I would wager theres alot more road bikers in the world than there are tt bikers ( by road biker, i mean everyone who owns a road bike, and that includes most triathletes.) theres probably alot mroe demand for the S2/3 than the P2, so obviously its also more expensive.
besides, why are you comparing the two? they were obviously built for different purposes, so its not fair to say that the P2 SHOULD be more expensive just ebcause its more aero.
true, the S2 and S3 are probably not as aero as the P2, but its not supposed to be, its a road bike, not a TT bike ( sure you could use it in a TT, but that wasn’t its primary design purpose.) . its meant as a breakaway specialists bike for road racers. for a TT bike, your primary considerations in the design are aero and probably handling. (weight and comfort are pluses, but these would be secondary consideration.s) . the S2/3 were designed to have the advantages of a pro-level road bike AND a TT bike, ( i.e. lightness, stiff, comfort, plus the aero of a TT bike.), so of course the S2/3 would be harder to engineer than the P2. it may not be as aero, but I’m sure the engineers spent alot of effort trying to reach a balance of those properties in the S series. I don’t ride nor have I ridden a cervelo, but I’m sure the S series bikes are wonderfully aerodynamic given the other considerations of geometry /stiffness/comfort that the cervelo engineers have to deal with. besides, the aero advantage of the P2 over the S series would mainly be in the geometry more than anything else.
If the P2 were superior to the S series in every way, why dont garmin-cervelo ride them in the grand tours? thats cos they were designed for different purposes. thats what engineering is about. define the problem, then come up with the best compromise to solve the problem, because its highly unlikely you’ll ahve an ideal situation.
if you were saying why the P3 was more expensive than the P2 ( but its not.), then yes, your case would be a fair argument. don’t compare apples to oranges.