I've sat on both sides of the interview table. I've been a lead looking for competent hires for a complex software project. My experience hiring staff can't be that different to the mainstream.
I'm amazed at the resumes I receive. I'm amazed at the quantity; about 100 resumes back in the day when we wrote newspaper ads. Somewhat fewer for an ad on hotjobs or monster. When I'm hiring, I don't have HR filter the candidates, because if they do, I don't get any resumes. I love the folks in HR, but they just don't know enough about software. So, 100 resumes in a pile, or 100 resumes in my in-box.
About 80 per cent of the resumes I receive are unqualified on their face for the clearly described position for which I'm hiring; retreaded poets and astronomers; guys with no experience at all in the languages or technologies I specified; people with no degree and no experience and no apparent ability to write grammatical english sentences. People whose home address is on a different continent (plus they have no experience). I guess these guys send a resume to absolutely every job posting, web site, and advertisement. They might as well not bother. These resumes go in the recycling on the first pass. (HR keeps a copy for awhile, because there is a requirement that they do so).
That leaves about 20 resumes that are worth a second look, which is to say a careful, front-to-back reading. Of these resumes, about 80 per cent are unqualified in some specific way. You can understand why they applied, but they are not the droids you are looking for. Not enough experience, not the right experience, or there's just something funny about them.
That leaves five resumes that are people you want to call up and talk to and maybe have in for an in-house interview. Of these five, there are maybe one or two (20% again) that you might make an offer to.
And there is another one who is lying to you. You bring them in for an in-house interview and their experience melts away. They clearly don't know what they're talking about. They just aren't what they say they are. Posers; fakes; cheats. And not very good ones, because you bust them in a couple of hours of interviews.
In the modern age, the barriers to submitting a resume are far lower, but there are more jobs. What that means to a hiring manager is more resumes that do not make the first cut, and fewer qualified candidates from whom to choose. You might not even get one candidate you want to hire, so your job stays open longer...and longer...and longer, while your team misses milestones because they are too few.
So, if it seems like your beautiful resume disappears into a black hole every time you submit it, remember that it's a needle in a pretty big haystack. If you get called, you made the first two cuts, the 20 per cent of the 20 per cent. That's pretty good.