Most people are considered experts because they were schooled and/or have a position.  I have learned more since graduating college than I did during all of my formal schooling and I have unlearned some lies I was taught.  Continual learning has made me more open to new ideas.

Today, most of the experts are more concerned with their credentials than staying experts in the subject.  They hold onto past learning (or indoctrination) rather than learning more and moving beyond their formal education.  They have forgotten how to learn and discover and think for themselves.  They are so determined to not be proven wrong that they refuse to even look at any evidence that contradicts their schooling.

Of course there are also those who only believe what is best for their paycheck.