Gary's job is easy. He works 102 days a year/5 hours a day. He openly say that he don't book guests. Guests have to contact Gary to be booked.
The reason is agents and their crazy demands. Just to ask an agency for an interview is 10000dollar. "Don't contact us if you cant at least pay 10000 dollars"
One example: Howie Mandel's agent Richard Del La Font agency.
The Agents are crazy. The website is crazy. Why should they get 10000 dollars just to ask their talent if they want to do an interview? This is also how shows can say that they don't pay for the interview. They pay the agent a "finders" fee.
BTW. Look at the page if you want to hire a talent for one gig. "Minimum 500000 dollars"