Equally the theory B-4 could evolve like Data was unfounded, Picard just assumed it.
I suppose you could, but it's a little more extreme. Also it's very different when it comes to people.
I think a good equivalent is those labour holograms from Flesh and Blood, they had no potential to be more than interactive humanoid-shaped tools. They weren't people nor could they ever be, the same could be true of B-4, his purpose could've been to just demo the physical model - see if the form could walk and talk, nothing more. If there's no potential or potential for potential, what are you left with?
Whereas with Data and the Doctor they overcame built in limitations, namely ethical subroutines - for example Data in The Most Toys and the Doctor in Critical Care overcome this pre-programmed sense (or limitation) of right and wrong. Personally I think displaying their free will was a clear sign of sentience making them people.
I'm not saying I think I'm right or anything but I just find it interesting, where do we define what constitutes a person in sci-fi?
Isn't "differently abled" a more accessible term? I mean it has far less negative connotations.