In an annual letter to shareholders last week, Warren Buffett, the chairman and chief executive of Berkshire Hathaway, urged his investors to take heart, because the American Dream is alive and well.

Even with diminished economic growth prospects going forward, Buffett, a billionaire investor known as the "Oracle of Omaha," says astounding gains are still possible. And that goes for small business owners too.

"Many Americans now believe that their children will not live as well as they themselves do," Buffett writes. "That view is dead wrong."

Clearly the dream is alive for Berkshire, a global conglomerate that owns about 60 companies including well-known brands such as Dairy Queen, H.J. Heinz, Fruit of the Loom, and Benjamin Moore, and holds large stakes in blue-chip companies such as Coca-Cola and American Express.

With a market cap of around $330 billion, Berkshire notched a healthy 6.4 percent increase in the value of its class A and B shares in 2015, according to the investor note. Over the last 50 years, its per share book value, which represents the value of the company's shares minus company liabilities, increased at a compound annual rate of 19.2 percent. That compares with the S&P 500, which experienced a 1.4 percentage increase in 2015, and a 9.7 percent compound increase over the last 50 years.

Buffett certainly takes the long view. He estimates that even with economic growth fixed at 2 percent and population growth of 0.8 percent per year, that amounts to 1.2 percent per capita growth. Over the next 25 years, that equals roughly an increase of $19,000 in GDP per person. Buffett estimates that works out to $76,000 per family if everything were divided equally.

Of course, he acknowledges, things are not divided equally between the rich and poor in a capitalist system. "Clashes of that sort have forever been with us - and will forever continue," Buffet says sunnily.

Yet like liberal Democrats including Vermont Senator Bernie Sanders and President Obama, Buffett favors expanding safety nets so, for example, displaced long-term workers such as the 1,600 employees in a former Berkshire holding called Dexter Shoe Co. who lost their jobs in 2001 are not reduced to penury.

"The solution ... is a variety of safety nets aimed at providing a decent life for those who are willing to work but find their specific talents judged of small value because of market forces," Buffett writes.

Even for those who make out less well, he says, over the next couple of decades market forces will provide opportunities to consume more goods and services than they have in the past, he says.

And for Buffett, it's business owners and businesses that will lead the way.

"America's golden goose of commerce and innovation will continue to lay more and larger eggs," he writes. "And, yes, America's kids will live far better than their parents did."