G. Mark’s Answer
If you look at the world around you and the incredible legacy that previous generations have left their mark on the modern world with, you'll see architecture. There are absolutely incredible efforts that people have made to leave their love and passion end effect on history. Some have labored with nothing more than love -- not being rewarded with money or accolades within their lifetimes -- to exert herculean efforts to produce some of the most beautiful and astounding creations in the world today.
You'll see some of the most incredible achievements done by humankind that were done simply because the people wanted to impact the world. Architecture is the greatest example of that.
You ask why would anyone be motivated to be involved at all in architecture let alone being someone who would exercise great influence on these endeavors. This is why.