Very few people claim they are sentient. The more common claim is that they have shown qualities that makes it reasonable to think that we are getting close to

Very few people claim they are sentient. The more common claim is that they have shown qualities that makes it reasonable to think that we are getting close to it - for very varying estimates of "close". If you were to look at human brain cells without ever having seen a functioning human brain built from one, you might well question if they'd be enough too.