True. We don’t follow precedent. But to an extent, we use precedent to figure out the halacha, which is based in the Gemara and our brains.
However, this isn’t entirely true. When there was semicha, a Beis Din had the power to actually be koveia halacha. The Gemara (I forget where at the moment) says that the reason the words of a minority opinion were recorded even though the halacha was hukva according to the majority, is so that a future Beis Din should have a precedent in case they wish to overturn the previous Beis Din’s halacha.