Depends on the person, and how they avoid working.
I can only speak to my personal observations.
There's the people who never get a job as an adult and so they never move out of mom and dad's house. Mom and/or dad end up supporting them until their deaths. I asked a guy I know whose son is 37, living with him, and doesn't have a job and hasn't had one in decades (and never worked full time) why he allows that sort of arrangement. He said "because I know he's got a safe place to sleep and something to eat."
There's people who have a kid or two and live off child support. In some states having a one night stand that produces a child with someone who has a salary of ~$120,000 is more lucrative than going to college and working the median salary for a college graduate. Even rape victims owe child support. There's two victims here, the person paying and the child(ren) who exist solely as a paycheck.
There's the related "bait and switch spouse," that's when someone, upon marriage (or cohabitation), just quits their job (or gets fired) and unilaterally decides they don't want to get another. This, of course, was their plan from the start. They may make the motions of trying to get a job to make it look like they are trying to work to their spouse, but the goal is to not work. They will ride this out as long as the spouse will put up with it, which can be decades. This is what my dad did, he basically worked for a couple weeks of my parents marriage and my mom has been footing the bill for him in the 4 decades since (and, no, he never took care of the housework or childrearing or anything like that).
Then, finally, we have the fake disability people. Claim you can't work due to pain, depression, anxiety, migraines, etc. Anything that's a subjective diagnosis. Establish a paper trail, then apply for disability. It really helps if you are in one of the above categories while doing this, because you have a history of "not being able to work" for the disability claim.