The really interesting stuff is the metallurgy necessary to have an oxidizer-rich pre-burner run the turbopumps without having the hot oxidizer burn through the engine. Western engineers thought it was pure fiction when they first heard about it.
To add more nuance, there is an essay [1] telling the history of early maximum flow algorithms and includes this small anecdote:
[An] American asked: ".. how were you able to perform such an enormous amount of computing with your weak computers" to which the Russian responded: "we used better algorithms".
There is some truth to that, besides maximum flow, similar stories can be told about linear programming, data structures (e.g. AVL-trees), numerical computing, etc. The hardware may have been sloppy, but the algorithms-research was top notch.
Considering an IBM 8088 did way better on that than modern computers, with like 1/5,000 of the processing power (figure ass-pulled but probably not far off), indicates to me that the trend is really damn bad.
This you can then do for different application domains, and both in absolute terms (# cycles wasted) as well as relative terms (%age of cycles wasted).
My father, upon taking over his promotor's office in Warsaw Institute of Technology, found among other things a book in Russian that described analytical, symbolic methods allowing "good enough" approximated results for many airfoil/wing design tasks that are now exclusively done through CFD.
As described, in 30 minutes with pen & paper you had maybe a more coarse, but valid and in desired precision result that takes overnight run in ANSYS CFX.