system
Given the following post, respond as if you're commenting on Reddit:
human
What happened to pensions?

For children of the 1950's and even 1960's, pensions were rather common.  In 1960, roughly half of private-sector workers had access to a pension, as well as workers for larger companies (GE, Goodyear, AT&T, etc).

401k's arrived, but didn't fully replace pensions.

What happened?
gpt
I believe what you are referring to are "defined benefit" plans. These were set up by companies and were supposed to deliver future payments based on your income and years of service (and other factors). The payments were often adjusted for inflation. These seem great, but they created huge liabilities for the companies. The benefit was defined, but there was no limits put on the costs. 

These were largely replaced with "defined contribution" accounts. In these accounts your employer would deposit money based on a set of criteria... The amount is much more easily predicted and does not create the potential for a large future cost.

So, the cost of pensions ended up being just too high for companies to maintain. These have been almost totally replaced with defined contributions -- The effect on employees is they generally receive much less total money from the company.