Some folks are good at this and some just aren't. Some people have all the time and energy to do the research and others struggle with finding the time to get things done without a wedding let alone with a wedding.
It's kind of like fixing a car or diagnosing a health problem. If you had the knowledge you could save yourself thousands of dollars. The point is that we all don't know how to fix a car or correctly diagnose a health problem, nor do we know how to plan an amazing wedding.
We do know what we want, well sometimes we do, but we just don't know all the secrets and tricks to the trade. There is a way to get the knowledge and learn what the professional planners already know without having to fork up thousands of dollars to get the dream wedding. Then again, the right wedding planner will save you money anyway!