I was Manston's CAA Aerodrome Inspector from 2001 to 2010, so saw much of the development. I watched attentively as the airport grew from a bare bones former RAF Station, expanding into...well not much really. Various change of owners, a couple of not so low cost operators and the fluctuating freight traffic. But as has been observed, not enough people in the area (also imagine how vibrant and active Lydd would be just down the road) and poor rail and road links to anywhere. Even dualling the A299 did not help much (I assume it's been completed all the way to Ramsgate now).
Basically, there was not enough dosh around to develop/expand the airport, or in the pockets of potential passengers.
There were some interesting challemges on those developments that did take place, such as the Bravo Apron and Bravo taxiway link (to runway). Due diligence and planning revealed the the airfield had been seeded with "pipe bombs" during WWII to be detonated in the event it was overrun by the invading Hun in order to deny use of the field. Plans showed the location of 21 such bombs, the condition of which was assessed as highly unstable as the original explosive material had decayed/transmuted into a far more voaltile liquid form. Anyway, the offending articles were removed by gentlemen of the Royal Corps of Engineers prior to proper development digging commencing. Only snag was when the RE located bomb number 22...and no way of knowing if there were even more (original plans probably made up in a rush and not updated). Tough decision. The bullet was bit and they went ahead anyway, presumabnly with fingers stuck in ears
. I made sure I was far too busy elsewhere in England while this was going on.
Mister B