What I discovered, decades ago, was that posting questions, or even better, answers, even wrong ones (unintentionally) is a phenomenal way to learn things.
That still holds true. Though it helps profoundly to not insist on being wrong.
I mostly focus on finding people with the answers. One person here I invited to another place specifically because they asked exceptionally, good questions. Most of the time, their questions led to more good answers or just perspectives. I'd like to see more of that.
I'm as well a long time lurker. Whenever I contribute something, I feel that it should be helpful for many other people out there. This comment probably isn't...
Ha! Well you made this lurker laugh, and reply! Also, it is not uncommon for me to write out a reply and then delete it before submitting because I second guess that the comment has value.
Another reason why people avoid contributing: unwritten social rules. New members often step on people's toes and suffer the consequences. As a result, joining a new group can be intimidating. Better to lurk for a while and gain understanding of what is and isn't normal.
That still holds true. Though it helps profoundly to not insist on being wrong.
Which I try to do. Not always successfully.