Doge on the other hand is a small coin, there is nothing that would make him really change a lot, it's going to be just doge and since it is easy he would tweet and it will skyrocket that's going to be the case for a long time. Obviously doge and bitcoin are different things, I think he could even pump ethereum if he wants and that's second biggest coin, but not bitcoin.
I do agree that a tweet from Elon Musk will not make any changes to the bitcoin market and the only time the market rallied is when Tesla invested over a billion dollars and i have not seen the bitcoin market rallying because of his tweets as the market is too big for his funny tweets to get a reaction but as you said Doge will increase whenever he tweets and that cannot be said about ETH as it has a much investor base as well. Only coins with lower market cap can be manipulated with a simple tweet.