Hardcore tech people and those who don't (or can't) trust institutions with their Bitcoin will pay the transaction fees to get their money out of exchanges and into their own wallet. The average retail investor, however, doesn't want to be their own bank. They just want in on the price action, while letting the exchange manage their money. Does anyone really think the person buying crypto $100 at a time in their Robinhood account wants to pay $18 (current average transaction fee) every time they want to move that BTC into their wallet? Of course not, which is one reason why Robinhood doesn't even have an option to withdraw Bitcoin.
As with any frenzy, the misinformation being circulated by people who want everyone to buy Bitcoin is getting out of control. How many average people buy Bitcoin because they think Bitcoin is the only way to avoid losing purchasing power? Meanwhile, everyone else has been protecting against inflation by purchasing stocks, real estate, or virtually any other investment long before Bitcoin was even invented. (Yes, I'm aware of the 21 million maximum BTC cap). The current Bitcoin narratives are more like a religion than reality.
That said, Tesla's Bitcoin purchase does make a lot of sense. Elon Musk went on Twitter and called Bitcoin "BS" to drive the price down so they could buy at a discount. They then announced their Bitcoin purchase with fanfare that drove the price up, marking a quick return on their investment. They used Elon's influence to make a quick profit on the frenzy.