apples & oranges. Those "rich" are almost exclusively from rich nations. Travel to the 3rd/developing world and see how many people of any class take part in high risk physical activities (excluding life!). The answer is close to zero. To extend, participating in high risk activities is a byproduct of societal wealth, not personal wealth. Remember it was the British of the 1850's, when they were the wealthiest in the world, who were the first major mountaineering nation.