The closing of the Rocky Mountain News in Denver provides a rare glimpse into the numbers behind the collapse of classified advertising at just one (well, two, sort-of) major metro — and its impact on the entire business model.

“In Denver, the steep decline in classified advertising alone has meant the loss of more than $100 million in highly profitable categories like help wanted and real estate,” John Temple, editor and publisher of the Rocky, said in his finale letter to readers.

That $100 million is a lot of money, especially since recruitment used to be the single most-profitable advertising category in any metro newspaper. At one newspaper I worked with, recruitment approached 80 percent margins — much, much higher than automotive advertising, retail, real estate or any other category. (Why the disparity? Pages full of recruitment advertising typically generated $20,000 to $30,000 in revenue; an auto dealer’s full-page ad might go for $2,000 to $4,000 because of rate negotiations, contract discounts, etc.)

The Rocky lost $16 million last year, according to parent company E.W. Scripps.

Assume for a moment that the margin on classifieds at the Rocky and its JOA partner, the Denver Post, was 35 percent. Perhaps it was lower, because of the peculiar circumstances of that joint-operating-agreement partnership and its lower-than-standard rates in Colorado, but it may even have been higher. No matter. Split the 35 percent — i.e., $35 million — in half (since the Rocky was one-half of a JOA, although it did not get exactly one half of the profits), and you’d have $17.5 million. Which neatly covers the $16 million loss and makes the Rocky break-even, or ever-so-slightly profitable again.

This is a flawed argument, I understand. And we know that $100 million ain’t coming back, certainly not in the form it was in before — ink on paper, relatively easy sales (or “taking orders,”), high margins and an unassailable (at one time) business model, with little or no competition.

Even so. Take that $100 million and apply it (or most likely a larger amount) at the San Francisco Chronicle. Or at the San Jose (Calif.) Mercury News, where recruitment advertising alone generated $183 million one year (a few years back during the early stages of the dot-com boom) and collapsed to just $13 million a few years later. Or at the Philadelphia Inquirer and Daily News. Or the Los Angeles Times, where the drop could easily be double that at the Rocky Mountain News and its partner, the Denver Post.

I hate to say “we told you so.” But if newspapers had rebuilt their business models for classifieds six, eight, 10 years ago — and we were singing this song as far back as 1997 — the picture might be substantially better, and the Rocky wouldn’t be just the latest (but biggest and most visible) in a string of newspapers to go out of business or cut publication from five days to two, or seven to five, and so forth during the past few years.

Now we’re working heavily to help newspapers completely restructure their classified models in desperation, rather than with a lot of foresight.

There are still classified advertising businesses and models that can and do work. Community papers are in the best position of all to serve their advertisers, if they do it right. But even major metros can capture, retain and regain share of a classified pie that is certain to rebound during the next few years. It will never be the cash cow that it was. But people will always need to buy a car, find a job, and buy, sell or trade cars. So there will always be a need for classifieds. The question is, “How will newspapers participate in that endeavor? And how will other media?”