Why do you think pension funds are in trouble all over America? There are no longer any safe investments that pay anything close to historical returns for such instruments. Therefore, pension funds are investing in exotic, rigged derivatives that seem to favor the bankers that write them when all is said and done, and which fail to replace the lost income. And if they pile into those "bond funds or equity funds which provide a good rate of return," they will be wiped out in the next crash (such funds crashed badly in 2008, many never recovering).
As for hurting bankers. the big banks themselves no longer depend on old fashioned simple interest income. They're out there borrowing money for roughly zero interest, and reinvesting it through their investment banks to get their money. They're also writing those derivative scams that the pension funds are buying.
In other words, since the repeal of Glass-Steagal, low interest rates help the investment banks. They only leave the smaller banks, insurance companies, and savers/retirees short of income. This is one reason insurance premiums are skyrocketing since the crash. Insurance companies used to be able to make a side income from safely investing temporary surpluses, but not now.
To top it all off, those "low interest rates" are rarely passed on to consumers. They're usually reserved for the Wall Streeters on the favored side of what Max Keiser calls, "The interest rate apartheid wall." The rest of us pay through the nose, or are simply told we don't qualify for the low rates.
You might think that housing would be an exception on rates, since low mortgage rates often do get passed on to borrowers. However, the Wall Street crowd used their cheap money supply to rush in and buy all the cheap housing after the crash, and that left housing prices so high, that the average buyer is worse off even there, because the loan's principal is now so inflated. But fear not, that also makes all those remaining leftover stockpiles of housing based CDO's and such on the books of the big banks look sound again, rather than threatening them with insolvency. That was exactly what the Fed wanted to see.
So no, low interest rates aren't helping the 99% in most cases, at least not when they're this low ...