[tcolvin]

Some aircraft were failures like the Whirlwind, Typhoon, Manchester, Bf210, and He177. But they were and never are called obsolescent. Just failures.
Some aircraft were a raging success like the Ju88, Mosquito and P51 whose wing-form was revolutionary.
I come back to the problem of placing the Battle.
Do we agree that technically it was par for its age, like the B17? It was not a failure.
In which case it was the RAF's requirement for the Battle and the aircraft specification met by the Battle that were obsolescent, and not the Battle itself. The RAF had no need for a day-bomber that lacked the speed of a fighter.
That was why the RAF never acquired the B17. And the USAAF's own need for the B17 was saved from obsolescence by the advent of the P51 which removed the LW's day-fighter threat.
Ironically the night-fighter threat remained to decimate Bomber Command, which then started flying by day in October 1944. The P51 would have made it safe then even for an updated Battle to return. Its obsolescence in RAF-speak would then have disappeared.
I rest my case.