Agreed, but perhaps more importantly, no-one in MoD is capable of constructing a "should-cost" estimate in sufficient meaningful detail to force certain companies to justify their programme costs, let alone allow MoD to manage their risks.
This was the job of the HQ posts I mentioned prior to early 88. Requirements were broken down in to Programme Element Costings (PECs, which speaks for itself), and the incumbent (for example, a single civilian HPTO was responsible for ALL RN avionics) worked closely with the MoD(PE) project Directorates (the technical project managers) to produce what all agreed were accurate as possible estimates. You may have got the estimate wrong, but you rarely omitted a whole programme element; which is common place today.
That HPTO post was the boss of the Requirement Managers - 4 of whom managed all RN avionics. (Today it is no longer a centralised function, so there are scores with a finger in the pie, but none who have an overview or detailed knowledge). I use that as an example as I held such a post in the mid-80s. Then you got promoted to the most junior grade in MoD(PE). THAT's the problem nowadays! Very senior people in DE&S don't know any of this, so although they may appreciate there is a problem, none understand the solution is to implement mandated regulations. (Which were never actually cancelled. They just did away with the posts and they naturally fell in to disuse). Still got my copy!