I see your hypothesis as too improbable to be worth worrying over. I expect to find instead that it all adds up to normality; the brain will explain the mind rather than explaining it away.
For those who have it, empathy and sympathy toward others stands or falls with empathy and sympathy for oneself. Actually that understates the case: self-concern beyond the immediate moment just is empathy and sympathy for oneself, even for those who only have empathy and sympathy for that one person. I boldly ;) predict robustness for these tendencies.
steven0461 (comment under "Preference For (Many) Future Worlds"):
Yvain (Behaviorism: Beware Anthropomorphizing Humans):
Eliezer (Sympathetic Minds):
So, what if, the more we understand something, the less we tend to anthropomorphize it, and the less we empathize/sympathize with it? See this post for some possible examples of this. Or consider Yvain's blue-minimizing robot. At first we might empathize or even sympathize with its apparent goal of minimizing blue, at least until we understand that it's just a dumb program. We still sympathize with the predicament of the human-level side module inside that robot, but maybe only until we can understand it as something besides a "human level intelligence"? Should we keep carrying forward behaviorism's program of de-anthropomorphizing humans, knowing that it might (or probably will) reduce our level of empathy/sympathy towards others?