The ancient Egyptians made pyramids to last forever. Wall Street’s pyramid schemes aren’t nearly as durable.

Bitcoin, while not officially a product of traditional Wall Street, is a pyramid scheme. A fraud. But it is best described as a “confidence game.”

I’ve been calling it a “bitcon” for a long time. And now the pyramid seems to be collapsing because fewer and fewer people have confidence that the price of this inherently worthless “cryptocurrency” is going to continue to rise.

I’ve just repeated some of the comments I made about bitcoin (and you could include other cryptocurrencies here) for years. But I’ve been especially vocal since early this year, when bitcoin was reaching nearly $20,000 in price and even staid Wall Street firms were being lured to this “investment.”

Here’s what I said about the crypto in a column on Jan. 4 that made predictions for the new year.

“The fact that anyone even has to discuss the fate of this and other so-called cryptocurrencies shows just how crazy the world has become. Bitcoin — or bitcon — is a confidence game. A scam. It will exist and move higher for as long as extremely wealthy people are willing to prop it up in hope that suckers remain confident that bitcoin has some value,” I wrote.

I predicted a number of times that bitcoin would eventually be worth $0.

On the day that column was published, bitcoin was selling for $15,144. That was below the $19,650 peak it reached on Dec. 16, 2017.

Over this past weekend, the price had fallen to just $3,600, which is still $3,600 too much.

Since its peak, bitcoin has lost about $700 billion in value. Think of it this way: The early participants in this pyramid have made a lot of money, but other people have lost $700 billion of their money in less than a year.

What caused that price decline? Nothing. That’s the same reason why bitcoin was once worth $19,650, or $15,144, or any amount.

I discussed this subject with a colleague last week, and she and I agreed that bitcoins are hard to write about. Why? Because bitcoins are the epitome of “thin air” investments. They represent nothing — not a piece of a company, or an ounce of precious metal or the faith in a country.

It’s like writing about philosophy. Bitcoin is a thought. And thoughts have value only if other people value them.

And bitcoin continues to be worth something only if its proponents can convince others to jump on board with the idea and bid up the price.

That’s the definition of a confidence game. You have to be confident that someone is dumb enough to keep investing in this scam.

Bitcoin’s value is certainly disappearing. And the only real explanation is that the confidence game is falling apart. The pyramid scheme that lured new money into this scam is collapsing.

When will bitcoin reach $0? I don’t know, although I did predict in another column that it would before the end of this year.

But I do know this: There are already investigations going on. And once the small investing suckers start complaining, the folks in Washington will get involved.

One report last week said the Trump administration is investigating whether people were propping up the price by purchasing bitcoin with other cyrpotcurrencies, which is like the mathematical equation “Confidence game squared.”

Since I am already on the topic of thieves, let’s talk about Christmas shopping.

We all know that there are people who do their holiday shopping with other people’s money. But how active will crooks be this holiday season?

According to a report from electronic payments expert ACI Worldwide, there will be a 14 percent increase in fraud attempts between Thanksgiving and New Year’s Eve. That’s only slightly below the expected 18 percent increase in the amount of goods purchased this holiday season.

Fraud attempts like illegal credit card purchases were expected to increase 17 percent between Thanksgiving and Cyber Monday, while purchases during that period were expected to rise 19 percent.

The stores are keeping ahead of the crooks — but just barely.

But give the crooks some credit. Erika Dietrick, global payments director at ACI, says thieves are going for the more expensive goods that are in short supply.

“Fraudsters will keep an eye on items that have limited inventory as it gives them an additional opportunity to steal and sell those items on the dark market for a higher price,” Dietrick says.

Nobody ever said thieves are uneducated in the Law of Supply and Demand.

Old-fashioned shoplifting is also a favorite of thieves. But this is interesting: According to the National Retail Federation, losses from employee theft are now nearly equal to those of shoplifters.

Employees now account for 32.2 percent of what is euphemistically called “inventory shrinkage,” compared with 35.7 percent for shoplifters and other outsiders.