Defined contribution plans are such a simpler system.
Defined benefit plans need professional actuaries to estimate a future with so many unknown variables: interest rates, rates of investment return, employee lifespans in 20+ years, retirement ages, voluntary employee exit rates (just to name a few). Plus you have the problem of so few companies lasting anywhere near as long as a pension plan would last, so these legacy pensions have to get offloaded to the Pension Benefit Guarantee Corporation.
It's no wonder that the private sector has moved from 30% defined benefit and 10% 401k back in 1980, to 2% defined benefit and 33% 401k today.
I think this is exactly right, a defined contribution is simpler, more transparent, and less risky for the employee and the employer.
The employee knows exactly how much the employee is contributing (and if it's being contributed in timely fashion), and (vested) contributions are safe from employer bankruptcy or change of jobs. The employee still has market risk, which was present before in that a pension with poor investment results may lead to the pension being assigned to the PBGC and result in a reduced pension.
The employer benefits by paying for today's workers only today, and does not have to manage and fund the pension.
There are certainly concerns about investment costs / poor investment choices within 401(k) plans, but I think some recent litigation results are likely to improve the landscape. Good plans are available, and companies may have a duty to provide a good plan.
It simply moves the investment work and risks to the individual. It's a minefield for the individual and vastly more complex to manage (individuals are effectively forced into being investment managers... like that's an easy job?).
It's ultimately just one part of the seismic shift in wealth to the 0.1%. "Sustainability" is just the thinly veiled excuse.
The employee already caries investment risk, although they have no control over the investments. If the employer chooses poor investments for their pension fund, it can lead to the pension being terminated. If the plan is insured by the PBGC, then some benefits are guaranteed, but the PBGC itself is underfunded: as of the 2015 annual report, it has $164 B in liabilities and $88 B in assets; if your employer can't pay its pension obligations, and teh PBGC can't either, that's going to be pretty complex too.
If the plan has any decent target date funds, it takes about five minutes to guesstimate your retirement age and pick that. It's probably not the best choice, but it's a reasonable one.
If market returns don't meet or exceed expectations, you end up broke on the street (and likely dead). (EDIT: Market returns have been, over the last decade or so, lower than expected; there is a school of thought that returns will no longer be as high as they were historically). [1]
That's the beauty of Social Security: it's guaranteed not by market forces, but by the existence of government. So long as the US government exists and has the ability to tax, those who rely on SS and Medicare will be provided for.
Defined benefit plans need professional actuaries to estimate a future with so many unknown variables: interest rates, rates of investment return, employee lifespans in 20+ years, retirement ages, voluntary employee exit rates (just to name a few). Plus you have the problem of so few companies lasting anywhere near as long as a pension plan would last, so these legacy pensions have to get offloaded to the Pension Benefit Guarantee Corporation.
It's no wonder that the private sector has moved from 30% defined benefit and 10% 401k back in 1980, to 2% defined benefit and 33% 401k today.