Mick Jagger turns 70 in July, well past a normal retirement age, and he’s got plenty of company. Each day, 10,000 people reach 65 in the U.S. alone. Unlike Jagger, the majority have a fraction of what they need to stop working. Ronald O’Hanley, president of asset management and corporate services for Fidelity Investments, says the U.S. faces a catastrophe if it doesn’t address the problems with its retirement system. Most working Americans have little hope of maintaining their current living standards when they retire, he adds.

With Social Security under pressure and defined benefit pension plans on the decline, defined contribution plans such as 401(k)s are becoming the main means of funding retirement. Under these plans, employees and employers contribute to portable accounts that enjoy tax-sheltered status until retirees withdraw benefits. Boston-based Fidelity is the country’s largest 401(k) manager, with more than $1 trillion in retirement assets.

O’Hanley, 56, joined the firm in 2010 from BNY Mellon Asset Management, where he was president and CEO. Senior   Writer Julie Segal spoke with him recently about proposals to limit defined contribution plans’ tax advantages and the mistakes that contributed to the retirement shortfall.

The Simpson-Bowles commission and others have recommended limiting tax benefits for retirement plans. Why do you oppose these limits?

First, the proposals are illogical:  They don’t raise a lot of revenue. Now contributions and earnings on that money are allowed to grow tax-free until employees start making withdrawals from retirement accounts. At that point, everything is fully taxed as ordinary income. Limiting the tax-deferred nature of these accounts doesn’t raise revenue; it just shifts revenue from the future to the present. I would argue it probably moves less revenue forward than if the government waited until the future, when investment earnings would likely be greater. If I wanted to be really unkind, I could call this another form of borrowing or stealing revenue from the future.

Point No. 2 is, these incentives matter. We have a lot of data on this because we’re the largest recordkeeper out there and we spend a lot of time talking to our plan participants. We know what drives their behavior. Even people too young to imagine retirement are still contributing because they like paying less in taxes right now.