Maybe you are right but people are still bringing it here and believe what he say's on social media. Well, we can't disclose the fact that Elon Musk is very influential, he is famous on social media which is very easy for him to gain attention from the public. But what he said about "the price of Bitcoin will rise", I think he is right from that as he never mention when. Whether he is right or wrong, no one knows. In fact, everyone can make their own speculations based on their market understanding.
"The price of Bitcoin will rise" is what I think that Elon Musk believe and those who are influenced by him would make them think that Elon Musk post is a prediction of Bitcoin's price. Why I say that is because of BTC's current price is not the same as before. I am sure you know what I meant. You are right that he is very influential that's why there's still people who follow elon's post and bringing it here to discuss.
It will definitely rise, but it is only a matter of time. Even if it falls to 5,000 US dollars in the short term, it will rise in the long run. It cannot be predicted in the short term, and there is no need to predict it in the long term.