One of my mothers friends, who is now in her 80's, has been retired on a pension for over 40 years. She started working for her municipality right out of high school at 18, and worked 25 years as a clerk to get a full pension. Retired at 43(!) with 75% final pay (annually adjusted) and lifelong medical benefits.
Its totally insane and completely unsustainable. Back in the day people usually keeled over at 65 and the US was viewed as having achieved infinite growth forever, so perhaps back then it was a reasonable but generous offer. Today however it's just straight up corruption and waste to offer benefits like that.
Some go on to another municipal job and get a second pension so they get paid twice as much to do nothing in retirement. I know someone who worked for the USPS then on to the NYC DoE as a janitor in a school. His wife worked for the public school system as well, then went on to work in a catholic school after retirement. Three pensions in one household. They invest a lot into long term investments such as bonds, CD's and the like. I hear they have millions in the bank.
The people who worked those jobs are all sitting pretty right now. I know plenty of people who made out like bandits in various NYC agencies, especially in the DoE. My aunt left her heirs 2.2 million and a house worth a million from her pension money she heavily invested and was still able to travel the world in retirement. She was a secretary in a middle school. Amazing what you can do with tons of free time and money.