You don’t actually “buy” domain names. You basically rent them from a registrar. “expired” meant someone forgot to pay rent / renew the lease so control of the name goes back to the registrar. They can just delete it after some grace period but domain names that has traffic going to them has value so they are usually put up for auction by the registrar nowadays, which is what you see here.

And we’ll leverage said feature until we become the market leader, at which point we will abandon it and begin the next phase of enshittification.