That's true. I feel like there is a bit of both here. Around the 1950s to 1970s, they were capable of some pretty impressive projects, civillian and millitary. Things like mass rollout of power infrastructure, road networks, city construction, the space race, etc. their GDP is today estimated to have been around half that of the US had at the time. Their growth in production numbers for tanks/planes etc
throughout ww2 was extrodinary as well. However they hit a real period of stagnation in the 1970s which just got worse and worse over time, i'm not an expert as to exactly why but my guess would be they developed a culture of corruption that continues to plague russia to this day