The big reason Robbie is riskier than his father relates to the improved safety in the ramps and the equipment over the years. When Senior jumped over the fountains at Caesar's Palace, note the small ramp. At the time, ramp designs weren't as CAD-advanced as they are today, and Robbie is paying dividends for having better design technology behind the risk-taking jumps.
Also lighter motorcycles make a difference. His Honda CR500 is a class away from his dad's bikes. The CR500 is a purebred motorcross bike, designed for MXGP competition.
Did Evil die. I could not find anything on him I though he passed away.