The same happens in many cases. What's a successful breakthrough is usually not only technological. UK was extremely indebted after the second world war, mostly to USA. https://www.exchangerates.org.uk/articles/1325/the-200-year-...
Of course there was the wider sad story of management problems in UK industry and the long decline after the war.
Our inability to follow through in recent decades can be depressing.
Hopefully SABRE/Skylon doesn't turn out to just be vaporware.
Having said that, London had food rationing for 9 years after the war, and really didn't have the money or facilities that the Americans had. (A B-29 was used as the mothership for the X-1!)
The W article below mentions "After the rocket plane experienced compressibility problems during 1947, it was modified with a variable-incidence tailplane following technology transfer with the United Kingdom."
https://en.wikipedia.org/wiki/Bell_X-1
Additionally, around half the X-plane pilots died, so Britain avoided a lot of test pilot fatalities. The US poured unlimited funding and talent into the program, with everybody being stars/aces (Yeager, Hoover, etc.) Both were injured seriously and almost died in various X-plane tests.
One X-plane test pilot set a record, then just quit and started a gun range.
The background is:
- Britain sent data on the Miles M.52 supersonic jet to the US, so at least some Americans knew about the flying tail before the X-1 (first supersonic flight in 1948), and the Germans did some work on flying tails
https://en.wikipedia.org/wiki/Miles_M.52
- most of the pre X-1 planes that crashed didn't reach Mach 1, but they did lose control. Those are called loss of control due to compressibility, not supersonic flights.
- as the article says, the DC-8 flew ok up to Mach 0.97 in previous flights, so they thought things were fine. Note that in every Mach 1.0 flight that I've read about, the airspeed indicator jumps from around Mach 0.96 to 1.0, perhaps meaning the indicator is not accurate around Mach 1.0.