My understanding is the SU collapsed for several reasons. One was that, as a centrally-controlled socialist economy, it because increasingly inefficient, as Hay

My understanding is the SU collapsed for several reasons. One was that, as a centrally-controlled socialist economy, it because increasingly inefficient, as Hayek explained. Another was that it had an economy only one-third the size of the US, but was matching it in military strength. This lead to so such huge expenditures that little was left over for capital investment in the rest of the economy. In addition, all the engineering and scientific talent went to the military sector, so there was little technological innovation elsewhere. Reagan looked at his and decided to greatly increase the US military budget, in hopes the SU would see it couldn't win, and quit the cold war. In addition, his technologists came up with the Star Wars idea, which was a scam they knew wouldn't work, but the hoped the SU would be tricked into thinking it would and that they couldn't match it. Fortunately, the Russian Politburo realized Russia was in terrible economic shape and needed radical changes, so they appointed Gorgachev to do this. And so when Reagan launched his plan, he eventually agreed to end the cold war. In addition in his attempt to rescue the Soviet economy he made radical political changes that eventually lead to the end of communism and the dissolution of the SU in to a number of separate states. So yes, Reagan's plan succeeded, but in part because of independent developments in the SU.