Short-order batches - one offs - cost a mega and are the cause of these "scandal" reports of £00s for a bulb or bolt. So, buy Economic Order Quantites, like airlines? Well no. Airline operation is at predictable intensity, so a balance can be made: best-value modification status, vs. stock obsolescence which condemns new kit from shelf to scrap. Except only for Airworthiness Mandatory items, airlines issue all their modification status A kit before releasing status B stock. Or that's what they try to do. The cheapest way is concurrently with original build to buy a life-of-type stock of bits. But that locks the User in to Day 1 status, losing the benefit of upgrades. Like running this screen on Windows Version Dawn-of-Time-You-Must-Be-Joking. I have that option for this, my innocent pastime. No-one is coming at me with harmful intent, with better kit than mine.
It's not Treasury. Treasury, alone, never cuts anything. Their bright young folk ask simple questions in the sense "Why do you want this thing". If the Buyer Minister has a good answer, he gets it. If not, not. Finite pot of gold; alternative uses...like leaving our money in our pockets. The Sun's front page + 2 more, on Monday, was Junk Jet, pics. of (they said: 60) Harrier GR9 stored at Cottesmore, shortly to be chopped. Scandal. Well, no. The collective of Ministers cut the Defence Budget. SecState for Defence, not the Chancellor of the Exchequer, offered up Harriers. If you want them to retain Harrier, then offer up something else. Or pay more taxes. Or vote in the other lot.