If an agent represents ten clients, the agent will usually try to help his priciest client first. There is no substitute for youth. So if you are trying to plan your career, think about which is the priority for you and aim for your goal. If you want to do art, don't expect to make tons of money, and if you plan to make tons of money, don't expect to make art. Virtually everyone who's had longevity and presence in Hollywood has serious emotional problems.
Sane people get out of the business and are never heard from again.
The business is more twisted than you can ever imagine. But no one will tell the truth. Don't believe what you read. Smiling is important all the time. People who think they are big shots are suffered for as long as they have clout, the minute they lose the clout they are out of the game permanently as punishment for their hubris.