Before leaving primary school most of us have learnt that whenever anything appears too good to be true, it usually is.

So some of us were sceptical when politicians were first heard to claim to have “put an end to boom and bust.” We had our doubts on being warned bird flu would be the death of us. We were unconvinced by promises of a “barbecue summer”.

The fact is forecasters, regardless of their persuasion, remain fallible. New paradigms seldom prove to be. And, as the cliché says, all good things invariably come to an end.

Consequently we were never persuaded that the flat rate “all you can eat” data plans on offer from mobile phone operators were sustainable in the longer term. Economically, they simply failed to make sense.

Having examined the numbers previously as part of another blog entry we were a little less than 12 months ago arguing we should get ready to say goodbye to cheap mobile broadband.

But to paraphrase Warren Buffet, for a while it seemed any forecast of ours would only serve to give fortune-tellers a good name.

However a couple of recent announcements might mean our prediction was not so much incorrect, merely a tad premature.

For example Mary Meeker of Morgan Stanley recently reported that in the United States AT&T had seen a 4,932% increase in data traffic over the last three years.

Such growth may not be totally unconnected to the fact that for much of this time AT&T have been able to offer their subscribers exclusive access to the iPhone.

At the same time a story in The Wall Street Journal makes intriguing reading.

“In Beaumont, Texas, and Reno, Nevada,” the paper stated, “AT&T has been pricing Internet access based on usage. Since last year, it has let new customers choose from one of six tiers, depending on the desired speed and how much data they think they will download in a month. Existing customers can keep their old flat-rate plan, which is capped at 150 gigabytes a month.”

The most basic of the six tiers offers 20GB for a monthly cost of $19.95. At the other extreme, subscribers prepared to pay $65 can have 150GB each month. There is then a charge of $1 for each additional gigabyte over those limits.

The WSJ quoted an AT&T spokesman as saying: "Some type of usage-based model, for those customers who have abnormally high usage patterns, seems inevitable."

In other words, what has already begun down in Dixie could soon spread to the major population centres on both East and West coasts, and then across the pond to Europe.

Because AT&T are not alone.

Again according to the WSJ Dick Lynch, the chief technology officer of Verizon Communications, informed a recent industry conference: "A flat-rate, infinitely expandable service is unachievable. We're going to have to consider pricing structures that allow us to sell packages of bytes."

Verizon of course have just begun to offer the iPhone to their subscribers as well.

And that takes us back to Mary Meeker. She also made the point that iPhone and Android users currently viewed many more HTML pages on their devices than owners of other smartphones.

What’s more, she said, quoting Mathew Honan of Wired: “Thanks to the iPhone 3G and, to a lesser extent, Google’s Android phone, millions of people are now walking around with a gizmo in their pocket that not only knows where they are but also plugs into the Internet to share that info, merge it with online databases, and find out what – and who – is in the immediate vicinity.

“Simply put, location changes everything. This one input – our coordinates – has the potential to change all the outputs. Where we shop, who we talk to, what we read, what we search for, where we go – they all change once we merge location and the Web.”

As a result, she concluded, thanks to these and other technological innovations, there was going to be a dramatic explosion in the number of mobile devices wanting to connect to the internet for an ever-increasing number of purposes.

And this, she suggested, was going to create many new opportunities for both businesses and investors.

Unfortunately, as the iPhone has conclusively demonstrated, the more sophisticated the device, the more data users want to download.

Already mobile networks sometimes lack capacity to cope with current demand, as iPhone subscribers to both O2 and AT&T regularly complain.

To be fair, Meeker does not completely fail to notice this particular elephant in the room, acknowledging “Wi-Fi is providing some relief to challenged 3G networks.”

Yet she appears to make insufficient allowance for the implications of her and Ovum’s claim that the number of 3G connections in Western Europe will grow more than fourfold over the next five years, from 126.7 million at the end of last year to 549.6 million by the end of 2014.

Think about it. No way will the existing mobile networks be able to cope with the consequences of so many ever more sophisticated devices demanding access to still more data. Nor will there be sufficient free wi-fi access points to compensate.

Quite simply demand for mobile broadband is about to outstrip network capacity. When that happens access prices will inevitably rise until equilibrium returns, with many users feasibly finding themselves unable to afford to fully utilise the devices of their desire.

Still, as Meeker approvingly notes, “tiered data pricing (speed, quantity) will likely be key to growing revenue long-term” for the network operators.

Yet surprisingly she still fails to address the possibility of consumer price sensitivity having any effect on her growth projections.

As we prepare to join the good folks of Beaumont, Texas, and Reno, Nevada in paying to consume our data by the gigabyte, we could soon learn the answer.

Or then again, if previous predictions predicate the accuracy of any future forecast, we may not.