I'd offer the theory that many people went feral during the COVID epidemic, but, unfortunately, some people have always been this entitled. It has to do with the values they are raised with. And it's not the people who legitimately would like to give their plus one or a sibling of the invitee a meal or gift or event they can't afford who do this -- it's people who could pay the extra or at least offer to. Before the event, after asking politely and being prepared for a no.