Regarding the OP's question, I think Mr. Musk is only into crypto to gather all of the attention from mainstream investors. This will help him take his companies to another level. Not because he's seriously interested in crypto/Blockchain tech. You can see why up to this date he's been speculating about a possible integration of DOGE into X, without making it a reality. It's all words, but no action. Once market prices go to the moon, he will reap the rewards while the rest will go "rekt" in an instant. That's the way it works. Only a fool will follow Elon Musk to make a crypto investment decision. Who knows what will be of Dogecoin once Elon Musk decides to abandon it?
Business owners do have the ability to create a buzz and Elon Musk is one of those who often creates public attention.
His goal is none other than to create attention for the company he is developing and he never cares about other impacts. I agree that a normal person would not follow him because he is a successful person and to make investment decisions it would be very stupid to just follow what he does.
Dogecoin did gain good momentum at that time, but the movement after that was a little slower.
If he leaves Dogecoin, it is certain that the price will fall because there is nothing more fundamental except his influence on the game in the public.
Whether Elon is using Bitcoin to increase the sales of his company, I don't think that is our business because the whales would also use their power to make things happen. He was able to successfully influence the price of Bitcoin and other altcoins too making more investors to join the crypto market. He has quite a strong impact in the crypto market and we don't have to discriminate him even though he is using the influence to increase the sales of his company. This is strictly business and we need to understand that. Everyone is looking for opportunities to make money for themselves and anyone of us will want to take the slightest opportunity.