How quickly should Vendors respond

I hear all the time that wedding vendors should be given a week to respond, especially during wedding season (now). That might be the way it is, but I don't like it. In no other profession would responding to a client a week later be acceptable. Everyone has a busy season at some point during the year. If I did that I would be fired, no matter how busy I was. There really is no excuse, especially in this day and age when everyone has their phone attached to them at all times. A simple "I received your message and will respond asap" would suffice. I don't get it. The vendors I hired all responded to my initial request for information within 2 days. I had a photographer that came highly recommended by my venue take a month...an entire month to get back to me. Yeah...I had moved on. lol