Really? That seems odd, where are you looking? Through your Carrier or just for unlocked devices? Depending on who you're with, usually you can just grab an unlocked device and your Carrier to register the device. I've only ever used Google Fi and AT&T though I'm not sure about the others.

Searching duckduckgo for 'Unlocked {device}' returns a lot of results on the shopping tab for phones on Amazon and eBay like the pixel 8/9 plus plenty of other "recent" android devices. Walmart and Bestbuy seem to still have dedicated sections for unlocked phones as well.