The review of the defence industry concluded that the UK was unlikely to ever build another aircraft by itself, but that the role of the UK aviation industry was to retain core skills by maintaining, modifying and upgrading the aircraft we operate. The shrinking size of the RAF means that has to include whatever is purchased to replace the Harrier. It also is a fact that through life costs are about 4 times purchase cost and that money needs to be spent here, not in the USA
We have a history of being let down in these matters by the USA. Skybolt, F-111 etc, and itīs no coincidence that, whilst others were buying F16s, F18s etc, we were spending more to build Jaguars and Tornadoes.
Trident was not seen as needing upgrades and, regardless, we never saw a need to go into the ICBM business. Our needed numbers are too small and there was nobody we could sell them too. There is also the probability the replacement will be a UK/Anglo-French ALCM. Same with TLAM, an off the shelf buy in small numbers with the same constraints. I have my suspicions that a longer term replacement might also be European.
The thing to realise is that jobs and industry tend to come out as higher priorities to politicians than future threats. If the choice is between the JSF, with all upgrades and repairs being done in the USA, and the Rafale with the French guaranteeing the work to BAe, the Rafale might well be chosen even if being seen as technologically inferior.