Ed Yardeni has a message for skeptics: the boom isn't over. The longtime Wall Street economist and market strategist is doubling down on a prediction he first made years ago that the 2020s could turn out to be a modern rerun of the Roaring 1920s. And if he's right, the S&P 500 could hit 10,000 by the end of the decade.

"I could see the S&P 500 getting to 10,000 by the end of the decade," Yardeni said this week in a podcast hosted by Wealthtrack. That's not just optimism talking. He thinks the fundamental forces driving growth are still firmly in place.

Surviving the Ultimate Stress Tests

Here's the thing most investors miss, according to Yardeni: the economy is far more resilient than people give it credit for. Think about what we've been through. A global pandemic. Complete lockdowns. Supply chains that simply stopped working. Inflation that made everyone nervous. Trade wars and tariffs. And now, some genuine weirdness in the labor market.

"We had the pandemic... the lockdown recession... supply chain disruptions... inflation... tariffs... and now we've got some funky problems in the labor market," he said. "And here we are at an all-time record high in real GDP... in real consumption per household... and the stock market."

In Yardeni's view, the U.S. economy and stock market have essentially passed a series of extreme stress tests and come out stronger on the other side. That's not luck. That's structural strength.

He sees genuine parallels to the 1920s. "The two decades rhyme and there are quite a few similarities," Yardeni noted. Back then, electrification and mass production transformed the economy. Today, it's digital technology and artificial intelligence doing the heavy lifting.

The Productivity Revolution Nobody's Talking About

At the heart of Yardeni's optimism is productivity. Much like the technological breakthroughs of the 1920s electrified that era's economy, today's investments in AI and digital infrastructure are quietly lifting output, keeping inflation in check, and supporting corporate profit margins.

Companies aren't investing in technology because they want to. They're doing it because they have to. If they don't, their competitors will, and they'll get left behind. That competitive pressure is creating a massive wave of capital spending that's paying off in higher efficiency across the entire economy.

"We thought that productivity would make a pretty significant comeback," Yardeni said. "That would have very positive consequences for economic growth, for keeping inflation down, for boosting real incomes of workers, and then, of course, boosting profit margins."

The numbers back him up. Technology now accounts for over 50% of capital spending, he noted. "Companies... have this attitude that they have to spend in technology because if they don't, their competitors will and will use it to increase productivity, to cut costs."

The $80 Trillion Consumer Engine

Then there's the American consumer, specifically baby boomers hitting retirement. Yardeni estimates that boomers are entering their golden years with roughly $80 trillion in net worth. That's an unprecedented amount of wealth for any retiring generation in history.

"As fast as we're spending money, our net worth just keeps going up," he said. Yes, the wealth distribution is uneven. But even so, it's creating a powerful tailwind for consumption that shows no signs of slowing down.

Why Rising Rates Don't Spell Doom

Yardeni also pushed back against the conventional wisdom that higher interest rates must crush economic growth. In his view, today's rate environment is actually closer to historical normal than the ultra-low levels of the past decade. We just got used to abnormally cheap money.

Meanwhile, capital markets have become much more resilient. The hard lessons from the 2008 financial crisis created deep, flexible markets that can absorb shocks and recover quickly. That's not a small thing. It means the financial system itself is more robust.

The Path to 10,000

Put it all together and you get Yardeni's bull case. If productivity stays strong and the U.S. avoids a recession through the end of the decade, corporate earnings can keep climbing even if valuations remain elevated. That's how you get to an S&P 500 tracked by the Vanguard S&P 500 ETF (VOO) hitting 10,000 points.

"And that's really not crazy numbers to anticipate," he added. "The resilience of the economy should continue to be visible in the resilience of earnings."

Just Stay Long

When asked for the best investment advice he ever received, Yardeni's answer was refreshingly simple: "Stay long."

"My only regret in my investment life is that I just didn't put everything into the Nasdaq and just, never looked at it," he said. "The Nasdaq has just been an amazing performer for years and years."

To keep his emotions from clouding his professional judgment, Yardeni mostly holds broad ETFs like the SPDR S&P 500 ETF Trust (SPY) and the tech-heavy Invesco QQQ Trust (QQQ).

"I try to have a portfolio where I'm not worrying about it, because then it can influence kind of my own work," Yardeni explained. "There's investing and then there's trading. And investing is going to make you money over the long run. Trading is fine as long as you don't have a day job."

It's hard to argue with the logic. Sometimes the simplest strategy is the best one.