"In any case, the principle of democracy is that the Russian government's legitimacy derives from the Russian people, not from leftists in the West"
Yes (and the same is true of Iran, too).
And also
"What if the Russians prefer a less authoritarian state with a slower growth rate and lesser industrial base to a more authoritarian state with a faster growth rate and larger industrial base like China's? Maybe the Russians are not so enamoured with fast growth of industry under an authoritarian state -- they have been there before, under the USSR."
I would be a bit reluctant to make the correlation quite so tight between industrial growth and authoritarianism - though certainly it is true that societies that squeezed personal consumption to facilitate a higher rate of investment often had to resort to authoritarian measures.
A low level of technology also tends to put limits on consumption, creating conditions that favour authoritarianism. So if China was your example, you would concede I think that Mao's regime was more repressive than the current one, I guess? (And fans of the Dalai Lama never really understood what a vicious system of social control the sedentary lives of the Bhuddist monks imposed on their people.)
Not wishing to understate its downsides, the post-war growth of west European societies corresponded with a liberalisation of those societies (with regard to divorce, abortion, censorship, gay rights), whereas the return of economic recessions in the seventies and eighties corresponded with a growing authoritarianism (on all the same issues), which seems to have relaxed again in the more bouyant (well, bouyant here in the UK, I forget that the US is in the throes of immiseration) nineties and noughties.