You are so right but I think it is not so simple. I don’t get invitations to weddings without knowing who it is, but I do get invited to weddings for people who I am not really in touch with anymore. People are very concerned about leaving someone off the list and hurting their feelings.
Now that I am making a wedding I have had to leave off a good chunk of people because I simply cannot afford to invite them. There are some people, however, who will feel very hurt by this and I feel obligated to spare their feelings over sparing my cost. And I am sure my disorganized nature has left me to omit many people I would have invited. I think most people know how hard it is to pay for a wedding and if the hosts stick to a list they can manage, people who are not invited will understand. And many people will be just as happy to have one less thing on their calendar.