I've always found it odd too that a large % of vocalists have no concern or responsibility for equipment. I've only met one vocalist who had her own PA setup for herself. Any other vocalist shows up and the first words are "wheres the mic I'm going to be using?"
This is known as LSD, or Lead Singer's Disease. This is often cured with a simple band meeting, but sometimes it can be fatal, resulting in the need to procure a new singer.