It was the point at which the Soviet Union realised that the UK needed to be counted as well as the US, in both military and political terms.
I'm sure we'd like to believe that, but I doubt it. The Soviet Union ultimately collapsed because it tried to keep up with the United States in the arms race, and went bust trying. I'd suggest that countering the UK post-the-Falklands had very little to do with it.
Love the Harrier though.