You can tell how well an audience liked your speech if, as you walk back from the podium, you look at those seated at the end of the aisles. If you’ve done well, most of them will be looking at you, smiling. If you’ve done poorly, they’ll look away, like a jury does to the accused when they return with a guilty verdict.

There were about 400 people in attendance. Mostly older folks. They were there to learn “how to create a $10 million portfolio.” In his introduction, the emcee had told them that the speakers were going to give them a bunch of “million-dollar ideas.”

Not surprisingly, they were visibly disappointed by what I had to say.

What I said was something I’ve been saying for as long as I’ve been writing about building wealth: Unless you have at least 30 years for compound interest to work its magic, you are not going to become wealthy by investing in stocks.

Here’s how I put it many years ago:

The investment business – and in that I include brokerages, private bankers, and insurance agents, as well as investment publications – is a huge and hugely profitable industry that provides a generally useful service. But it is populated with smart, ambitious people who promote one teensy-weensy lie.

The lie is that you can grow wealthy in less than 30 years by investing in stocks and bonds.

 It’s not a big, black lie. There is plenty of evidence that strategic investing can provide returns that exceed costs (brokerage fees, management fees, subscription fees, etc.) and even produce positive returns after inflation. But for that to work, you need time.

Say you start with $50,000. And you follow a tax-deferred investment strategy that has been proven to deliver 10% annually, year after year.

At the end of 10 years, your $50,000 will have increased to $129,687. At the end of 20 years, it will have grown to $336,375. And at the end of 30 years, it will be $872,470.

$872,470 will give you $87,200 of income for 10 years, which might come to about $65,000 after taxes. That’s okay. But it’s hardly wealthy.

Besides, you probably don’t have 30 years to wait before you would want to begin spending that income.

So what’s an earnest wealth seeker to do?