also a captain in the redarmy would probably have been conservatively 25-35 so would have remembered the aftermath of the Russian civil war and have immediate family who remembered the poverty of the tsar and civil war. Russian wealth was not static in the time in between and standards of living drastically improved so the fact he thought it was a lot doesn't necessarily mean it was much better than the soviet union at the time as the standards of reference for wealth might well have caught up slower than the standards of living
also a captain in the redarmy would probably have been conservatively 25-35 so would have remembered the aftermath of the Russian civil war and have immediate family who remembered the poverty of the tsar and civil war. Russian wealth was not static in the time in between and standards of living drastically improved so the fact he thought it was a lot doesn't necessarily mean it was much better than the soviet union at the time as the standards of reference for wealth might well have caught up slower than the standards of living
It might have been from Max Hastings' "Inferno" but I'd have no way of checking that right now.