The "nearly half" remark is referring to the previous sentence regarding 42% attrition. The paragraph could have been structured better, and I wouldn't say "nearly half" until the 46% mark or so, but it isn't as bad as "29% == half".

I have a hard time believing stats like these ever since I learned about "ghost jobs".

A full 2/3rds of jobs posted to hiring boards are "ghost jobs", i.e. postings where the employer does not actually intend to ever hire an applicant.

Why do they do this? To appease overworked employees in understaffed departments. They can say "We're looking for someone, but no-one wants to work these days!", when the reality is they're keeping the department short-staffed to maximize profits.

This happens in the department where I work. My direct supervisor would always complain that HR "wasn't really looking" for people to fill vacancies and the only way I, and everyone else, in the department got hired is because she recruited us manually.