I think that is a fantastic click through rate for something that passively shows on a feed. That's probably about as high as you can realistically get to be honest. Most posts get sub fractions of 1% click through rate.
For any random feed link that was not requested, just passively shows up to everyone that happens to follow Elon, it is a fantastic click through rate. Please show some data on passive feed click through rates on social media sites.
Given that Twitter just changed the algorithm to artificially inflate Musk's tweets, I think a tweet from him could well be considered a paid advertisement at this point. A very, very expensive paid ad.