That said... we're not saying we need to respect the natural world any less, or need to force sapience on all animals. We might just want to give some the ability to reach our level (however good or bad it might be) and converse with them honestly. Otherwise, how are we ever going to have a moral answer on the value of sapience, if we're the only ones who ever have it?
And naturally there is no "responsibility" externally. All ethics arise from us since no other beings capable of complex cognition are present within our immediate vicinity.
Certainly one can argue for respect for all living beings and I think one should be able to construct such an example easily. My one great moral horror is that I recognize diminutive intelligence in animals that I still would gladly farm and consume. One day we will be called to task for that. My hope is to be long dead by then.
Who decides what is of value, that "sapience" is an absolute value we are required to work towards? There is no answer to this we have access to except we ourselves decide.
Therefore, there is no "responsibility" from outside ourselves, certainly not some kind of external responsibility to prioritize some values (creating more "intelligent" species) over other values (not creating frankenstein monsters with capacity for incredible suffering).
I think living beings that lack recognized-by-us "sapience" still have their own inherent value that must be respected. To suggest that becoming more like us is their only destiny is to disrespect them as they are, they don't need to be more like us to be respectable.