Looks like whole theory is wrong

I used hookpad a lot and get many knowledge and inspire from it, but last time i analyzed most popular music closer, and realize than most of great music don`t use notes. As example this tab: https://www.hooktheory.com/theorytab/view/michael-jackson/thriller
I analyzed bass line in original and actually its play not by notes, frequency steps between notes is less that half tone. Its play between keys most of the time. That’s why piano version sounds cheesy and wrong dont matter which note you choose. And that why all well-known music theory has not many sense.
Does some one noticed than some time one half tone sounds too low but next one sounds too high and you feel like you need something between?
I added this topic not because dont like hookpad, i want try to move it deeper.

Someone once told me you have to play the melody ‘In the Mood’ in Bb, any other Key doesn’t ‘sound’ right. Does the Key make a difference? I don’t know!