I was recently job searching and roughly 50% of all jobs ghosted me. Just an automated email and then... silence. And when applying via LinkedIn only ~5% of companies even opened my application.

I can believe that your company has a good reason for keeping the job up, but I also know that some job ads are black holes were no one bothers to do the bare minimum including taking the posting down. I have no idea how to differentiate one from the other.

50% is a pretty damn good response rate! I wouldn't complain about that.

It's not surprising about LinkedIn. They've made applying for jobs too easy so there's too much noise. I wouldn't bother applying for jobs there. LinkedIn is great for recruiters though - just put some effort into your profile, set it to "looking for work", and then reply to interesting recruiter spam. That's how I got my last 3 jobs.