> nobody wants to buy it, you have no case for a trademark. That's weird.

It may seem weird if you're thinking about it from the perspective of a business owner trying to protect their brand. That's why a business would want one. But it isn't why they exist. The legal basis of trademarks isn't brand or business protection, but consumer protection.

The point of a trademark is to protect consumers from being fooled or misled. If there are no consumers, then there's nobody to protect.