Bavli is superseded by "sifrei Halachah"- the Halakhot books actually dethroned the Talmud as the standard text used by law-makers, to the extent that they evolved into texts that could function as an updated Talmud."
Ever teach Talmud to a Jew who knows ONLY Kitzur Shulchan Aruch? It's a real challenge - because the student thinks that every Halachah in Kitzur is an axiomatic given, and he cannot fathom how it is - that Rabbis in the Talmud debate this stuff!
There is a historical parallel. The arrival of the Bavli to Western Europe probably occurred around the year 1,000. Aside from oral and mimetic traditions - what Halachic texts did they have?
Apparently in Ashkenaz the She'iltos, the Halachos G'dolos, and similar Gaonic Halachic compendiums arrived earlier. They took root as normative texts, although local Minhag may have prevailed.
I discussed this idea with Rabbi E. Kanarfogel, a PhD in Medeival Jewish History. He found the idea "interesting" that the earlier arrival of later texts may have "idea framed" how Ashkenazim read the Bavli as it trickled into Europe. IOW, their minds were pretty much made up Before
The Bavli came - and every attempt was made to read the Bavli based upon the pre-existing texts and traditions.
Thus, dissonance grew between the simple read of the without any pre-conceived notions, and the read of the Bavli framed by incorporating Gaonic Texts as well as mimetic culture.