It is time to talk about why people act, and, thusly, why they don't. People participate in amateur plays because they are great social centers, they are fun, and they get noticed by their peers. It is also great fun to act. Aristotle noted that 2000 years ago. Many people find it exhilerating to be in the spotlight and they have egos that respond to the attention associated with acting. Some are compelled to be actors. They may not be able to explain it, but they have to be actors. All of these reasons may drive these people to attempt to become professional actors, and a very few of them will succeed. Some may have reasons other than those I have mentioned here, feel free to comment.
People do not act because they fear being closely observed by their peers, or they do not think it a worthy activity. Others simply have no desire to do so. Yet, many who want to act, do not act because they have lifestyles that prevent them devoting the necessary time for it, or they have doubts about their ability to do it well. It is really easier not to act, than to act; and therein lies the reason most who say they want to act do not act. Acting requires real devotion and determination on top of talent. It also requires a pleasant and even attracting personality.
The sum of all this is that it is up to the individual to act or not to act. It is a personal choice. So if you say you want to act, get acting, there are always places like community theatres that need actors and there are things to do to become a professional if you are quailified.