[zimpenfish]

> performance improvements such as in chunk loading and map generation

True but the general game loop is still (wildly) inefficient; hence the multitude of performance mods (Sodium, Lithium, FerriteCore, ImmediatelyFast, etc.) that are considered basic mods for anyone wanting to play the game without dipping down to tragic fps.

All of that functionality could (and should!) have been folded into the Minecraft source years ago. But Microsoft didn't buy Minecraft to give people a good experience - they bought it because it generates a non-trivial amount of money from things like Bedrock IAPs, merch licensing, etc. Updating the games is just a necessary evil that keeps the money flowing.

(Bedrock, on the other hand, is much more optimised because, IIRC, the core game was written in C++ targeting mobile devices and needed to be efficient to even work.)