Following up this conversation. Did some research.
Almost immediately after acceptance in service there was a request to designers to start working on new models of "avtomat-carbine" as a successor for SKS, and for "light avtomat" as a successor for AK47. Simonov provided almost 10 specimens for trials, Kalashnikov provided also provided his vision for "avtomat-carbine" and his specimen was favorable. At the same time Kalashnikov specimens for "light avtomat" project were able to show results in accuracy similar to carbine, while keeping benefits of firepower of "avtomat". Probably seeing this and probably communicating these facts (these are just my assumptions and not facts) we have 1955 decision of Ministry of Defense to stop pursuing "avtomat-carbine" project and unify these two projecting into one - "light avtomat" project. As as result Kalashnikov again wins and his project accepted in Apr 1959 as "AKM".
So, in conclusion, I guess it would be correct to say that AKM has displaced SKS, however in the same manner it is correct to say that AKM displaced AK47. And both are results of 1955 decision about "unification" of the "carbine-avtomat" and "avtomat". I haven't yet found this 1955 document, nor have I seen commission reports (I'm 99% sure they are still classified, that why BTW well know author Chumak said there would be no book about SKS anytime soon and his book on AK is limited on pre-acceptance period), it would be interesting to see details, though post ww2 is not my main area of interest.
P.S. Kalashikov's "avtomat-carbine" M1952 project samples
"6-100"
"6-103", slightly different one
Video of "6-100", unfortunately only in Russian, where R. CHumak says "...development of "light avtomat", that was intended as replacement for both "carbine" SKS and "avtomat" AK-47". So I think I got it right with other sources.
https://kalashnikovgroup.ru/media/kalashnikov100/kalashnikov100-avtomat-karabin-kalashnikova
P.P.S. This source (
https://www.forgottenweapons.com/wp-content/uploads/2015/12/1978-01-17b.pdf) was originally provided by this guy, he was executed for treason
https://en.wikipedia.org/wiki/Oleg_Penkovsky
P.P.P.S. And the was a movie about him, that had been waiting for 3 years in my "to-watch" list.... gotta see it now.
https://en.wikipedia.org/wiki/The_Courier_(2020_film)