Rivet Joint
I can answer that simply, a significant part of the problem lay with a succession of technically deficient appointees to the roles of Operations Director and Airport/Managing Director. For many years blissful ignorance reigned with a refusal to listen to those of us who had the competence to identify the problems and the long term impact on airport development.
The location of the Short Term car park relative to Stands 7-12, and the restrictions it causes to size of aircraft which can park thereon (only currently circumvented by the CAA's agreement to permit the owners to fudge the CAP 168 obstacle clearance rules), is a monument to this.
For many years my colleagues and I pushed for a northern taxiway. After the missed opportunity when the asphalt making plant was on-site during re-surfacing, future attempts were kicked into touch by the party line that there was insufficient room to build it. Funny how, when more car parking space was needed, the ILS Glidepath equipment was replaced (to make it more obstacle tolerant) and a car park was built where the taxiway could have gone!
And as for declining to buy the site where the Post Office building was eventually erected, removing the chance of extending the current apron and building an extension to the current Terminal Building? Why do that when you can build a new Terminal 2 miles from the current one on the east side, on a green field site, having to duplicate staffing and services, and create a near nightmare scenario when trying to get people between the two buildings (either a tunnel, not forgetting to divert the main gas pipeline which runs around the northern boundary; or a road with traffic lights to ensure obstacle clearance due the adjacent runway end). Should be interesting to see what the minimum flight connection times for PAX transferring between Terminals would be!