In my experience, over time, freeloaders tend to become vocal and lobby for policy changes (within the team, not corporatewise) that helps keep them there. I've seen them oppose technically sound decisions because they're not sure they can handle the complexity, or (and more commonly) because it involves skills they don't want to learn. Skills well within their reach if they just tried - some of them had those skills in school and they merely need to get a book and review what they once knew.
Generally, if you're a motivated person, but in a team with a significant number of "freeloaders", your ability to raise the bar of the team will be limited. I left my last team because of it.