I mean, the above comment leaves open that there are many reasons. Is it so crazy that he would use money to take down the account after offering money for the owner to take down the account?
You assume that he wasn't just trying to make it worth the guy's well for a bit of privacy. He didn't think the guy had any other reasons to be tracking his plane than making a quick buck through his donations page. He stopped bothering once he realized the guy had petty ambitions for fame. (Which btw that guy continues to play up for the media and drags out the idea long after Musk has dropped it.)
Personally, I am seeing this a potential way to limit the freedom even more on Twitter than already happening.