I knew a lot of people who did well for themselves in the 90s and retired in the early 2000s.
My FIL was laid off in his 50s and is doing just fine: he had been hoping for a conservative boglehead retirement, though. I don't think he would be spending much, if any, more, he would just have a more conservative withdraw rate and leave a bigger legacy.
I have cousins who went to work for the local factory at 18 and retired with full pension at 48. That was right around the crash, no idea if that is still a possible career path in the rust belt.
I know a number of people who retired from the military. Some went on to second careers, some didn't.
I currently have one friend who has mentioned early retirement and making lifestyle choices that will allow it to happen.
I also have friends who are SWAMI. They like what they do, as business owners they are employing folk, and the business is run in such a way to allow for frequent travel and a near constant staycation attitude to their hometown. They have admitted that they could maintain their current luxurious lifestyle indefinitely and still have to worry about how much they are leaving it to their daughter in a way that won't cause more harm than good.
I know far more people who quit their jobs and went adventuring, with the intention of going back to work, or in modern times, intending to work remotely. As a matter of fact, that was our original plan: save up 10 years' expenses in taxable, then wing it. Turns out, with the introduction of HSAs and learning about mega backdoor Roth's, we will be pretty close to that goal soon, but with a much higher net worth than we originally projected and a lot less left up to "wing it."