Developed, yes. Productive, god no.
I picked the examples, because sitting here at work, those were the data points I could pull out from memory. If you dont believe that my data points are representative of the whole, spend some time on the internet and at the library. You really have to work hard to make a case that the Soviet economy of the 70's and 80's was anything other than an inefficient, unproductive mess. Hell, the Politburo itself knew it, which is why Andropov was so intent on making reforms before he died. Again, oil was the only thing keeping that economy going during that era.
Try comparing the Soviet economy to India in the 70s and 80s. Or Argentina. Or Brazil. Compared to them, the Soviet economy looks shiny.
Or try comparing the Soviet economy of 1960 with the Soviet economy of 1980.
No, it wasn't. The USSR in the 70s and 80s was extremely unproductive and inefficient compared to its western counterparts.
In agriculture? No question, it was a huge mess.
But, as an exercise, compare the Soviet car industry to the British car industry. Or indeed, the whole British economy with the whole Soviet economy from, say, 1976 to 1985.
Again, I think it is important to revisit this: the USSR was doing very poorly in comparison to, say, Japan and the USA - but Japan and the USA were the two leading economies in the world during the period of Soviet collapse. And we forget by just what a large margin they were ahead by! Outside Europe, Canada/USA, Oceania, Japan and the Soviet Union the world was really darn poor back then. South Korea was still a 3rd World country. Taiwan, Malaysia, Singapore - also all third world. China was not just third world, but really, painfully, stonkinly poor, even for the third world.
So being "one of the leading economies" back then was a much lower bar than it is now. And lo, the Soviet Union was providing goods and services to its citizens that were well ahead of what was available to the average citizen in the third world. By most measures (both then and now - though analyses done in the 90s tended to severely overestimate Soviet economic weakness - sort of an overreaction to the unexpected collapse) the Soviet Union was providing goods and services at about the the average level available in the developed world (but where exactly they came is still something of a hot argument - after all, how do you compare the value of economical bus fares on an extensive public transport network against economical Japanese cars than can be driven on an extensive state-run highway system?)
It isn't that what either of you are saying is wrong - the Soviet Union WAS an unproductive, inefficient mess. But I fear you are focusing on those messes, and in doing so ignoring the context of what the larger Soviet economy and the world of 1980 were like.
Possibly, my opinion on Soviet economics may owe something to my opinion on Soviet politics.
To illustrate: Had the world economic circumstances or the internal political circumstances been different, then the USSR might well have overcome her 80s malaise, just like Britain overcame her 70s malaise. But the USSR wasn't Britain. It didn't have the internal political flexibility and it didn't have the external political flexibility (i.e. it had less capability to cooperate with the rest of the world). So if GOSPLAN had successfully planned the Soviets a bit more growth in the 80s, it wouldn't have mattered. If GOSPLAN had planned the economy worse in the 80s, also, I don't think it would have mattered. The political problems were sufficiently severe that I think it could have snatched defeat from the jaws of any victory the planners could have achieved.
fasquardon