I call this 'reading for the plot'.
I also suffer from the same issue with remembering names. I wonder if the two phenomena are related.
I sometimes wonder about where the value of reading (fiction) comes from: is it the plot and trying to figure things out before they are explicitly explained? The little details? The long, lyrical passages? The act of reading itself? Something else? I'm curious what your thoughts on this are.
Emotionally, it's certainly enough to get attached to characters, which is the point. But the way my brain likes to read (it's not a conscious decision, just the way I do it), is to skip a lot of the description, and get to the interesting bits (dialog, action scenes, etc).
I certainly miss out some subtleties, but if you and I read the same book we could have a meaningful discussion about it, probably without you realizing that I likely read it in half the time and only paid attention to about 80% of the content.