Philosophical debates (which are the case in the “robots rights” concept) are not meant to be confined to space and time; they are there so we may learn from them. Who knows what will come of this theoretical discussion, it might even better our lives today or help us study the past.
The intellectual philosophical concepts thinkers develop today are not product yielding, nor were they product yielding in the past – there for there is no sense in asking what does it “worth” thinking on “robots rights” today.