Elon or other influencer will gradually lose credibility as long as their tweet/opinion influence the market against the interest of most users. Just like how it happen with McAffee.
That being said, immunity against this kind of manipulation at all times is probably impossible unless traders and crypto investors start ignoring individual sentiment of the market.
They are smart to know when they should do manipulation. If Elon, example, see his tweets don't have too much effect on the market, he will change to become less or no actively tweet about cryptocurrency.
This change will create curiosity in followers and when he tweets again, after months, his tweets will be appreciated again. Who don't want to see Elon Musk tweets? His tweets can be toxic but affect the market and if you see a market is at the end of any triangle, his tweets are funny to support a break out or dump. Very interesting tweets with correlation to market.
I don't like him but I like his tweets as I like Trump's tweets 2 years ago. Trump tweeted, gold price was dumped to negative price. Days later, Trump tweeted again and gold price recovered.