Why does everyone but me always have something to say?

Quora is terrible. The top answer is their resident bot account, for some reason. The question may also have come from a bot in the first place. The replies are interwoven with adverts. If the question is really from a person, there's no interaction for clarification or context. It's all noise.

Not to be a cynic, but perhaps you have nothing interesting to say? Who gauges what's worthy of being said anyway? At the end of the day at the bottom of the chain it's you (when it comes to your thoughts). Some people don't have a filter and just say whatever. Others are more conscious/aware/ashamed and even if they voice their opinion they feel some sort of resistance/shame etc. (for one reason or another) OR they never voice their ideas, or share their opinion. You should ask yourself and reflect on why do you even ask that question in the first place.

The Internet and social media create the illusion that everyone is talking and making because people get as many 'votes' as they are able and willing to post. Face to face we see the people who are just listening and are perhaps bothered by someone who goes on and on. On most websites and social media platforms, sonmeone who is not posting is invisible.

Historically the old web had 10 to 100 lurkers per commenter, and 10 to 100 commenters per person creating new threads or topics.

Quiet: The Power of Introverts in a World That Can't Stop Talking, (2012) Susan Cain.

If I feel I have something worthwhile to add to the conversation, or some related story, I speak up.

Otherwise, I listen and learn, and quickly decide if and when it furthers the conversation.

It really isn't about ego (or karma points)

The time for ego signaling passed long ago.