Graham,
It could be said we were buying an American aircraft in the Harrier II AV-8B / GR5 ; There was still a lot of UK development to do, and it certainly didn't feel like it was being done for the sake of it !
If we really accept things off the peg, there will be tears if such kit ever actually has to be used ( but it would be fine parked behind a politicians' dias or wazzing past at airshows ).
However I sadly feel the overall gist of this thread is probably accurate; the rot set in when RAF accountants overcame BAe accountants by making out OEU work is 'free' which it clearly isn't, as well as introducing penalties such as this state of capability decay.