Well, I wouldn't say it was just a handful sitewide. (Though absolutely in individual subreddits.) But those with very high karma (earned through upvoting) have way too much influence and easily overshadow users with lower karma.
Lower karma doesn't necessarily mean the user's posts aren't good. (You start with 0 karma.) It can just be really hard to get seen to earn upvotes if your karma is low.
You know the ridiculous problem with job experience? How it's hard to get a job without any job experience, but you can't get job experience because no one will hire you because you don't have any job experience?
Yeah. That's Reddit.