After the crisis, policymakers believed that making the banks stronger would bolster their lending. In many ways, this outcome has occurred. Since the end of 2010, banks have added $2.5 trillion of loans, a 37 percent increase, according to data from the Federal Reserve. Over the same period, their profits have soared. In the first quarter, the industry as a whole reported its highest profits in recent decades, according to data compiled by Federal Deposit Insurance Corporation.

The six largest American banks — JPMorgan, Bank of America, Citigroup, Wells Fargo, Goldman Sachs and Morgan Stanley — have done particularly well. They made $141 billion in pretax profits in 2017, nearly double the $75 billion they made in 2010. The tax cuts enacted last year have provided a particularly large lift to the bottom lines of banks. A strengthening economy and higher interest rates are expected to further increase earnings this year.

Those behind the post-crisis regulatory overhaul say the robust economy shows that more or less the right amount of regulation was imposed. Barney Frank, the former congressman who helped sponsor the Dodd-Frank Act, said, “I have been struck ever since Trump came into office by his bragging that we have the best economy that ever existed anywhere and his insistence that regulation was damaging the financial sector.”

The stress tests suggest that the banks can withstand punishing losses. They assume, for instance, that Bank of America can suffer $50 billion of losses on its loans and still have ample capital.

But good times in banking can lead to complacency among regulators and bankers. So while banks are definitely stronger, some prominent skeptics would prefer that more be done to make sure taxpayers are never called on again to bail out the banks.

“The question is not: How do banks perform when the economy is strong?” Neel Kashkari, president of the Federal Reserve Bank of Minneapolis, said in an interview. “The question is: How do banks perform if there is a major economic downturn? And our analysis at the Minneapolis Fed says that the banks are still too big to fail.”

Mr. Kashkari, who was a Treasury official during the crisis and oversaw the government’s bailout of the banking industry, said he believed that a crucial part of regulators’ post-crisis plans for winding down failing banks — turning a bank’s debt into equity — would not work in a real crisis. To stop a collapse of the system, he said, taxpayer bailouts would almost certainly be required. Instead, regulators should have banks substantially increase their equity, Mr. Kashkari said.