This industry is horribly inefficient and intentionally so. It's mostly east-coast based - NY/DC but functions similarly to the LA entertainment industry.
The main problem is this:
You are a meeting planner (not your job title, you are actually a marketing person or executive assistant) and your boss just tasked you with find a speaker for your next company meeting.
What do you do? You can either:
1) Find a speaker yourself by searching Google and sifting through the mess of results
2) Call a speaker's bureau and get raked over the coals on price
3) ???
Ideally, there would be a marketplace for speakers. Where you would be able to search for talent that fit your criteria (available these dates, for this price, talks about these things, is well-regarded, etc.) and book them online.
Nothing like this exists.