I'm not the OP, but I've noticed something similar myself. I still have certain things I'm passionate about. But I no longer feel the need (or rather I don't just automatically become invested in every topic that comes up in my environment).

People do outrageous things in the world, and an earlier me might have had a self-righteous anger about it. Today, while I certainly have an intellectual care, I have the luxury of putting such things out of mind and just enjoying my day. I still take proactive steps to better the world where I think it makes sense, but not out any emotional fervor. I save my passions for my family, hobbies, and a subset of professional interests.

I haven't read the book, but from the abstract, I suspect "The Subtle Art of Not Giving a F*ck" by Mark Manson is basically where I arrived. I have learned I have only so my F's to give, and so spend them more wisely.