Embrace the Quiet Ones
Not everyone is meant to be a salesman.
While everyone is being taught to be more "outgoing" or that you "need to make more friends", there are the ones that are just... quiet. These are the people that enjoy the time they have by themselves whether its a book, drawing, or writing, they are not people who thrive on the presence of others. These are called introverts. In the today's society, everyone is in a way brainwashed by models, advertisement, TV, movies, etc to think that you must be liked by everyone and speak very well to be successful in life. However The very iphones that so many people use nowadays were created by the pretty quiet Steve Jobs.
Participation does not decide knowledge.
In school, this "salesman" mindset is still a very present thing. Just like how i'm sure many people may not like their business out for everyone to hear, whether it be family issues or personal life, quiet and introverted kids don't want to be forced into being noticed. So always making kids do things like presentations, acting, and put on the spot to answer a class question will make some kids feel violated of there personality. So a suggestion would be to encourage work environments where kids can do group activities while also encouraging spaces where those kids who do better by themselves go about the work independently.