What is the most profitable and most enviable business in the crypto world?

Exchange? Of course, unless you're at the top tier; and most top-tier exchange owners have stepped on a sewing machine at some point. Except for Brother Sun, Nurse Xu, Mu Mu, Big Brother, and Old Black, they've all been involved.
Exchanges are indeed very profitable, but the money isn't as easy to come by as you might think.
Many people may not know, or may not have noticed, that there is a company in the crypto space that is doing better than any exchange. A company with about 100 employees, with annual profits exceeding $10 billion, and an average profit of $100 million per person. That is Tether, the USDT issuer!
Its business model is very simple, and a single sentence can make it clear: users hold dollars and exchange them for USDT; Tether then uses users' dollars to buy U.S. Treasury bonds, enjoying an annual yield of around 4%.
Currently, the USDT market size exceeds $150 billion, and by 2025, based on conservative estimates of U.S. Treasury yields, it will generate about $6 billion in income.
But it's unfortunate that ordinary people can't enjoy Tether's profit dividends; all the profits are divided among shareholders. As a top-tier company, it neither issues its own tokens nor goes public.
Meanwhile, as a compliant stablecoin issuer, USDC has a market size surpassing $70 billion. The biggest difference from Tether is that USDC follows a compliant route and, with the backing of a U.S. publicly listed company, it is the only stablecoin asset that ordinary people can purchase in the stablecoin sector.
Many altcoins may die out, but stablecoins could become more and more widely used. For example, simply put, I now use stablecoins (U-Card) to buy Twitter blue verification; such scenarios will become more common.
Bold prediction, or rather, visibly accelerating: stablecoins originated in the crypto world but already possess the aura of a global payment industry infrastructure king.