Yet the Soviets kept on producing those prop powered Tupolev Tu95 Bears and others well into the 80s, and Putin started patrols and the intercept game up once again. Think they've now been repurposed as cruise missile launchers as well as bomber. So the Lightning kept flying into the 80s, then Phantoms and eventually Eurofighter Typhoons would be going to play with the Bear nearing airspace. The intercept role was expected to disappear, but hasn't. The newest intercept role is the surprisingly frequent post 9/11 intercepts of civilian airliners that go silent or otherwise raise suspicion. UK has Typhoons going supersonic over land every few months. So despite expectation, it never quite went away.

You're right about the brain drain, but it would have been nice to see Avro continue, and no doubt had they been building Arrows there would have been a more air superiority/longer range mark III -- they did already have mkIII plans, and ideas for even faster, after all -- as roles adapted. Above all, Avro Canada might still be in existence and competitive.