The reason why NFT artwork is worth millions isn't just for a speculative market so another chump will buy it from you at a higher price, but it also has another value. Like all artwork it is used for tax avoidance. The high price of NFTs allows a wealthy elite to squirrel away millions to accrue value without being taxed. They are more handy than a real piece of artwork or some expensive property in London because a digital image isn't vulnerable to physical damage or maintenance costs. It's obvious why this shit is exploding.
Oh for sure, only the 0.01% or higher who can afford this do this. You're right that most investors are doing this because they hope to sell for more than they buy, and will have to pay capital gains tax.