This is a reasonable instinct, although, as I argue in the book, it really only explains things after the 1975 KGB-advised decision to harness the Soviet IT industries to cloning western innovations. Before that decision, between 1959 and 1975, when the Soviet networks are getting their start, the Soviet computing industry is often pioneering and interesting. After 1975, Soviet deliberate technological just-behindness does not equate to technological backwardness. One of the takeaways of this story is that peerless imaginative foresight, technological wizardry, and political prowess are not enough to change the world.
> After all, layered copying of Intel x86 CPUs also was 'pioneering and interesting'.
It was; at some periods I think Soviets were world leaders in electronics reverse engineering. Those techniques were rumored to get used well after USSR death in some Asian countries.
MESM -> BESM-6 machines I've heard had some abilities like a number of simultaneously supported IO ports (AS system for space program?) - which may or may not be considered pioneering. Another example is Setun ternary computer; of course that's providing we should consider some computers after ENIAC 'pioneering enough'.
That's the one that rings a faint bell, for me -- ternary systems. Although I've no background to speak of and suspect, based on their work in mathematics et al., that there is considerably more to the story, including and perhaps especially on the theoretical side.