Getting an email from a recruiter is a whole lot different than getting a job offer.
Getting 30 job offers a month probably would be as great as the author thinks. But how many of those 30 recruiter emails will lead to job offers? Probably zero.
My beef with recruiters is that they repeatedly pitch me jobs that I know their client won't ever hire me for. They're not only wasting my time, they're wasting their client's time, too.