Gents,
In my limited experience, it is very easy to overlook the amount of effort it takes to fully engineer what would, at first glance, seem to be relatively trivial changes. When all we wanted to do was move a couple of lights around on the QE to tweak the Bedford array for SRVL the price was huge - because all the ripple through of all the sub-structure and wiring changes was significant.
It's easy to think that you just go out and buy an EMALS shipset for 400 million, get out your arc welder, bodge it on for a few million more and off you go. I don't pretend to have the foggiest idea about ship-building but I doubt it's that simple. You're assuming the deck's sub-structure was perfectly and fully designed for the EMALS and arrestor gear and their mounting points (or whatever you call the things that you use to attach a piece of equipment that is designed to accelerate or decelerate 25 tones of aircraft in a couple of seconds to/from 150 knots). But you also have to bodge on an LSO platform somewhere and all their comms requirements, move all the lights that were set up for SRVL onto the angled flight deck, and I shudder to think of what you have to do with things like electric power cable looms, electro-magnetic compatibility testing, qualification and certification testing, jet-blast deflector installation & their cooling requirements etc.
I assume any headline costs discussed these days include the full Defence Lines Of Development analysis - so they'll factor in the costs of all the extra personnel you need on deck to use cats & traps, their training, accommodation & pension costs (over the 40-odd year life of the system), the logistical costs to maintain the cats & traps, the costs of disposal etc etc.
Don't get me wrong, I'm not saying that i think 1.8 billion is a bargain, but it doesn't surprise me. I'd love to see a huge UK carrier battle group steaming around the world with a deck over-flowing with F-35C, F-18E, E-2D, C-2 and some Sea Kings (just for old time's sake). However there are good reasons why the US DoD budget is >10 times bigger than ours.
Regards,
Single Seat, Single Engine, The Only Way To Fly