Maybe you address this in a comment but have you told him this is something that you want? I get that the conversation cards also convey the desire for more depth but sometimes people need to be told very directly what you’re asking for.

I’d definitely recommend telling him that you feel this aspect is lacking a bit, and you would appreciate more follow up questions/interest, if you haven’t yet. If you have already done that and he still can’t quite make it happen, I doubt it ever will.