I haven't yet looked at these sources (I say wish some shame, as I really need to get to speed on the Soviet collapse), but Chomsky recommended the following:
"There's an interesting book by David Kotz and Fred Weir on the collapse, and a lot of work by many others, Moshe Lewin to mention one. Somewhat underestimated, in my opinion, is the role of the Kennedy administration. It rejected Khrushchev's call for reduction in offensive weapons -- which he unilaterally implemented over the objections of the Soviet military. The JFK administration reacted to his moves by sharply increasing the already huge military US military advantage, and then insisted on humiliation of Khrushchev rather than a straightforward diplomatic resolution at the missile crisis. This led his downfall, and sharp turn in policy, where the Soviet Union tried to match the West (mostly US) in military power. As Khrushchev was well aware, that would sink the much weaker Soviet economy, as it did. Into the 60s, the Russian growth rate was very frightening to US-UK leaders. In the 60s, the economy began to stagnate. Kennan's comments, which you quote, seem to me basically right. There's good discussion of all of this by Raymond Garthoff in several major books."
"Kennan's comments" here refers to his NYT editorial "The GOP Won the Cold War? Ridiculous": http://www.pentaside.org/article/kennan-nyt-gop-won-coldwar.html
Tayssir