That doesn't jive with my experience. When I look at the people I've worked with over the years, all having a blank profile says to me is that they don't care

That doesn't jive with my experience. When I look at the people I've worked with over the years, all having a blank profile says to me is that they don't care about their LinkedIn profile. I know the quality of their work and it seems to have no relationship with how detailed their profile is. Personally, I list every project I've worked on, what my role was for that project, and the technologies used. I do that for my own benefit as well as for recruiters.