The writing on the wall for a totally buy British Aerospace policy was really the TSR-2 - the cost of developing it and building it was eating more and more of the defence budget
You have to be able to pay the costs of the industrial base, the research base and actually have enough money to buy and operate the damn things on a continuous cycle - you can't "take a break" between programmes
If the Yanks are running into problems there is no hope for the UK
Joint development works up to a point but all I can see is more and more old airframe programmes being stretched to infinity - it's not pretty to be maybe having to consider stick new wings and new engines on a 50 year old B-52 but who can afford the zillions and decades required to replace it?