Billy Joel sang that only the good die young. Perhaps they die young because they have nothing to lose so they are more likely to do things that risk their lives. Those with something to lose are often far less likely to participate in actions that can hurt them, whether it be physically, emotionally, financially, or in any other manner. The reality is that everyone has something to lose - no one is invulnerable. The difference is that older people, or those with families, are typically more cognizant of that fact. And if they recognize what they have to lose, they are far more reticent to change anything that could impact them negatively.
When put in the context of revolution, the contrast is stark. Revolutions are often started by the youth of a nation while their success often depends upon the support of the middle class and some of the elites. Several examples come to mind, including the failed protests in China in 1989, the failed protests in Iran in 1999 and some of the "color revolutions" that occurred in Eastern Europe after the fall of the Soviet Union. A great majority of those who came out to protest their governments were students and other youngsters. In spite of the dangers of crackdowns by the governments they were protesting against which often resulted in beatings, arrests and even death, they came out in the belief that their presence would result in a change that would grant them what they sought. In some cases, their presence resulted in enough pressure that they were soon joined by the middle class who had previously stayed aloof for fear of loss and they would find a leader from one of the elites who sensed an opportunity to ascend higher. In other cases, they suffered disastrous consequences.
But why did they risk themselves in such ventures? The reasons are myriad and sometimes perhaps even conflicting. It would not be a platitude to argue that many of them sought freedom, though that term is subjective and was often interpreted differently by those who risked themselves. One example is China during the spring of 1989, when the students protested against government corruption as well as the ability to be able to do better for themselves. While they enjoyed a great deal of support among the general populace and even among some of the leading elites, their protests were eventually crushed by an apparatus that was unwilling to tolerate any criticism and feared a loss of its unlimited power. It could be argued that the protests did succeed in some small measure as official corruption has become a persistent whipping boy of the government and the great majority of Chinese have seen dramatic increases in their lives in the 20 years - all of which is claimed as a validation of and by the government and its brutal crackdown of those student protesters.
But it is important to note that the protests began among the students, as they have for much of the last century in China. The great majority of citizens, middle-class and elites, held back from participating in the protests until it appeared that there would be no forceful response from the government (which occurred due to disagreements within the government as to how to handle the protesters). That the protests failed was not as important as who led them. The initial risk (which is always the greatest) was assumed almost exclusively by the students. Whether one agreed with the risk - and it can be rather certain that the parents were not happy for their children to risk themselves - the students felt the risk was minimal to themselves. Perhaps out of ignorance, perhaps out of a false sense of bravado, perhaps the naivete of youth that it is invulnerable, the youth were the ones to strike out on the new path. It was for the remainder to determine whether the path upon which they set out had a destination that could be reached.
Each new generation spawns new ideas. The lessons of the past are often left in the past - a past that only the older generations can recall with ease. Much like the story of Pavlov's dogs, if punished for taking a particular action (or for putting their necks on the line), then they are less likely to do it again. But for those with little experience - good or bad - then the lure of taking risks is sometimes too strong to resist. And with great risk can sometimes come great reward. But the opposite corollary holds equally true in that that risk can be realized. One of the definitions of risk is "the hazard or chance of loss" (http://dictionary.reference.com/browse/risk). To understand risk and loss, each generation must first experience it.