Eh not really, it's just a resistive heating element + impeller + temperature sensor + microcontroller. And implementing PID and tuning the parameters is not that hard as it's such a common and well-known algorithm. I built a sous vide cooker myself with a 500W heating element and tuned it well enough to hold +/- .05 degree in a matter of a couple afternoons for like $20 in parts.

The difference with a commercial product is first and foremost safety. You've got high current electricity and moving parts in a high temperature environment, all underwater. The difference between what I made and something like the Anova is that the Anova isn't going to kill someone and also it will work reliably without the user needing to fix and tweak stuff (and that by itself is a feat, considering the environment an immersion cooker is designed to operate in). If I sold what I made as a product it would break and kill someone.

All that kind of engineering and also the important work of optimizing user experience is not something manufacturers of most rice cookers care about. It's not worth the extra engineering effort. That said, there are some pretty fancy high-end rice cookers that have pretty precise control and maybe these sort of features may creep in on those, but that sort of rice cooker is a whole different beast than the little Panasonic cooker that lives on my counter.