People running businesses generally have little free time. This is especially true when it comes to attending business conferences. While they need to keep updated on what is occurring in their industry, leaving to attend a conference takes time out of their busy schedule. Travel each way generally takes at least a day between getting to the airport, flying to the destination. Even attending a minimum number of panels or speeches takes a day or two. Busy executives see this as largely unproductive time.
The world has become increasingly competitive. Business leaders might have been willing to attend several conferences per year in the past, but that is no longer true. Even taking the time to attend one conference is often seen as too much. Organizers for these conferences do their best to entice executives. They book the best speakers, exhibits and industry leaders. They also try to host their conferences in convenient locations for the majority of people attending.