REALLY interesting line of thought. May I ask what prompted this?
There may be a measurement challenge here: How can the sentiment (pro/contra altruism) be tracked?
Once we figure that out, I'd be interested in seeing if the sentiment is cyclical over time (particularly decades).
I don't agree or disagree. You have interesting ideas, but they don't seem cohesive to me. Suggest giving them more thought, applying very specific hypotheses, and outlining arguments in favor/contra.