Per vehicle mile traveled, motorcyclists' risk of a fatal crash is 35 times greater than a passenger car.
In 2012, the US had 23 fatalities per 100 million miles ridden. If you do the math, riding 4,000 miles a year for 40 years gives you a 4.2% chance of dying in an accident. That's just death. It doesn't include getting crippled or having permanent brain damage.
You would be crazy to ride in a car that gave such a high risk of death. In fact, any car that dangerous would not be allowed on the road, and any excuses about mitigating risk would be laughed at. It is an accident of history that society allows motorcycles. If they were invented today, there would be zero chance of them being allowed on streets.
Paradoxically, the only sane place to ride a motorcycle is a race track. With no obstacles, large run-off areas, trained riders, and plenty of armor, injuries are minor.