Most rich people like Bill Gates and Warren Buffet are against investing in bitcoin or cryptocurrencies in general because of the huge risks due to heavy volatility. I'm very bullish on bitcoin and cryptocurrencies, but it's indeed a huge gamble. "Moon" and "lambo" gains aren't guaranteed. We're just pretty much speculating and hoping that it would indeed rise to very high prices.
Rich people will never tell you the way to get rich and if they see you trying to make something for yourself they are the first to give you negative advice. People like Bill Gates and Warren Buffet are company owners with shares/stocks to sell if they let everyone buy bitcoin who is going to buy their stock? So, what they are doing is another business strategy to blackmail bitcoin since it's a competition to their businesses.