This is part of the reason I see a lot...Wich I also don't understand, by making the add the person has already set themselves up to be the middleman, if you don't want to be a middle man don't get involved right ?
@Dabbler has good points, I never considered autism may be the reason, I also agree, the seller gets to set the rules for contact, but if both parties are motivated a compromise should be possible
I don't think people are loosing the ability to communicate without a screen, I think people are busy, and a phone call needs to be addressed *NOW* vs when you may actually have time to give it the proper attention. I also believe phone calls give a lot of people anxiety, making or taking them, and I don't think that is new, it's just that now emails and texts are accepted forms of communication.