Three years after the financial crisis and the bailouts, and we’re not much better off: “Too big to fail” remains, banking profits are sinking and those big, overregulated banks can’t manage to lend to small businesses.

Maybe it’s time to stop protecting this failed business model — and finally begin to break up the nation’s largest banks.

Making them smaller and less “systemically” important may be the only way to get them to lend more. If they hold less capital, they can start taking some risks without a chance of blowing up the whole financial system.

The obvious way to force the banks to get small and fast is to again split commercial from investment banking — that is, making it so that no bank can roll the dice in the securities markets if it wants its deposits backed up by federal insurance.

That’s the conversation inside Bank of America, where people tell me the commercial banking part of the firm is far less profitable than the investment banking unit, formerly known as Merrill Lynch.

They also concede that, by selling off Merrill, the bank could pay down some liabilities and toxic assets it still holds on its books from the 2008 crisis, which are dragging down earnings and caused BofA shares to dip below $5 earlier this week.

Maybe by being smaller and stronger, BofA can start lending again to small businesses.

I say this as someone who has covered Wall Street for two decades and witnessed firsthand its transformation into the massive seething mess that it is today.

The shift began with the creation of Citigroup in the late 1990s, which combined under one roof both an investment bank that took risks in various markets and a commercial bank that lent money and held insured customer deposits.

Then, in 1999, President Bill Clinton and the Republican Congress drove a stake through the 1933 Glass-Steagall Act, which had officially divided those activities. The megabank rapidly became the order of the day, as mergers and acquisitions built such behemoths as Bank of America, while old-line investment banks such as Goldman Sachs and Morgan Stanley felt compelled to snap up commercial-banking units to better compete.

The sales job from Wall Street told us that being big had competitive advantages — it let US banks go toe to toe with huge foreign players. But as profits exploded, the banks’ fatal flaw was largely ignored: They were too big to manage.

There were signs — like the bungling at Citigroup, which under founder Sandy Weill found itself mired in just about every scandal of the day, from Enron to WorldCom to “research” sold to investors that really catered to its own investment bankers.

But it only became obvious when the banking crisis hit, and the guys managing the megabanks suddenly found out they were basically insolvent and sitting on countless billions in toxic loans and investments — and that without a taxpayer bailout, the collapse of such large and interconnected banks threatened to bring down the global financial system.

Somehow, that experience failed to convince the banks’ overseers that bigger isn’t better, after all — far from it. From the Dodd-Frank law to the new Basel global-banking standards, the trend is just the opposite.

The result: Fewer than a dozen US banks now hold about 75 percent of all bank assets. But because they’re so big, regulators force them to hold mountains of capital — lest they crater the global financial system with a single screw-up.

With all the new rules and regulations, the nation’s big banks still aren’t doing what most Americans believed the bailouts were designed get them to do: lending to small- and mid-sized businesses that are the engines of post-recession economic growth.

Under the new laws, banks have little trouble lending to such global megacorporations as General Electric, which the regulators deem less risky than smaller, all-American entrepreneurs. But how many jobs is GE creating here? Few, as it turns out.

At least some people, like Republican presidential aspirant Jon Huntsman, see the benefits of the smaller-is-better banking model and are starting to talk about the need to make the banks smaller and nimbler.

But don’t expect much action soon. The megabanks don’t want to change, and most of Washington — with the Obama White House leading the pack — likes the power (and access to campaign cash) that the current setup gives them.

As for economic growth, who needs banks to do the investing? The feds can pick the winners of the future; I hear there’s a great one called Solyndra.

Charles Gasparino is a Fox Business Network senior correspondent.