Remember back in the 1970s when a favorite pastime of Utahns was to sit around and bemoan the fact that they could have bought Park City land a decade earlier for a couple of hundred dollars in back taxes?

That's a scenario Richard C. Ben-nion foresees repeating itself in a few years when investors look back on the "good old days" of 1989 when industrial land in Salt Lake County could be had dirt cheap . . . but they didn't take advantage.There's a lot of vacant property out there being ignored by investors, says Bennion, principal broker for Salt Lake-based Commerce properties. True, developers will buy a parcel they need for a build-to-suit structure, but there isn't much being bought on speculation. Ben-nion sees that as a vote of no-confidence in the local economy.

"That's going to continue until people begin feeling a lot better about Utah's future," said Bennion. "It's an indication of how we feel about ourselves."

Actually, Bennion notes , Utahns in general and real estate investors in particular are even now beginning to come out of the blue funk they've been in for the past few years and are making guardedly optimistic noises once again.

That may be all that's needed to get industrial land sales moving again and prices along with them. Bennion points out that local industrial land can be had for $1.50 to $2 per square foot compared to $10 or $15 in Southern California.

"People will look back to 1989 and say `I could have made a lot of money,' " Bennion predicts.

But if the industrial land market is still a commodity waiting to be discovered, industrial real estate overall is already showing signs of renewed life after several years of dormancy.

Commerce Properties has just completed its 1988 industrial real estate absorption study, and it indicates the kind of movement that landlords like to see.

For one thing, there wasn't much new industrial space built last year, only 448,000 square feet, down from 1.18 million in 1985. And there was a 22 percent increase in the amount of industrial space absorbed last year: 3.87 million square feet up from 3.17 million.

This combination of low construction and increasing absorption means one thing to Bennion: the law of supply and demand is finally beginning to work in favor of building owners.

"The good deals in the market may soon be over," said Bennion.

He said the prices of "junk" space - buildings that have been glutting the market for years - have finally fallen low enough that it is being leased up.

"This means the worst pain is finally easing. Properties that no one has been able to sell have been sold and are being converted to other uses."

Bennion estimates that there is now only a six-month supply of available industrial space in the 0-5,000 square foot range; about 18 months' supply in the 5,000 to 20,000 range; and 19 months of 20,000 and up. He believes a 6-7 percent vacancy is an ideal inventory and the current rate is 9.5 percent - only 2-3 percent high and well below vacancy rates of recent years.

"What surprises me is that with such a small amount of available space, prices are still soft . . . It indicates the market is stronger than it appears. People think it's bad, but it hasn't undergone the pain of office or retail space."

Bennion predicts 1989 "will be the year we catch our breath" and 1990 will see the market begin to tighten and rents start to rise.