I've heard so many stories lately about dignified, accomplished individuals losing touch with reality as they age. 

These people are typcially very wealthy. They are used to being at the top of their fields, respected, and sought after. They aren't used to being wrong or to having their judgment questioned. As they get older, they are less and less in touch with things as they are.  They become more and more self-absorbed.  They engage in these self-aggrandizing activities. They can't stop talking about themselves. 

People end up perceiving them as someone who was once great but is now comic yet sad. They're looked upon with pity and embarassment. 

And they have no concept that they have diminished.