The problem is that claiming a device requires a handshake between the device and the cloud to authenticate, so it must be online.
For Wi-Fi products, it’s common to have the end-user claim them at the time of Wi-Fi configuration, so this is not an issue.
For cellular products, many product creators claim all of the devices to a single account controlled by the company. This is typically done during setup and configuration of the devices.
That being said, a way to use product devices without claiming is something that’s being investigated, as it would eliminate a step that’s a pain for large deployments. I don’t have a time frame for that feature, however.