i think it's a mix of culture, AND...It's The Economy, Stupid. On both the parent's and the child's end.
i'm 23, just graduated college, and i've been living back at my mom's house since last June. i had been living on my own in the dorms/off-campus houses, taking care of all of my own bills, except for the actual rent (part of the contract in my parent's divorce, they each
had to pay for my board so long as i was in college. dunno why my dad did that, but okay...

i didn't complain!).
now that i'm out of college, i do plan on leaving...eventually. Grad school, hopefully, and hopefully farrrrr away.
But right now? Things are cool. There's no freakin' way i could afford a place on my own right now, and after having various roommates for 4 years i'm aaaaallll set with that for the moment, hahaha.
And, honestly, i'm a help to my mother - my house is WAY too big for just two people, and so with me there, i can help with the dogs and cleaning and cooking and all that stuff. My stepfather is the definition of a lazy slob, so if she didn't have me there to help out, she'd flip. (Which, i've realized, is why she was kind of a psycho when i was younger, and had yet to develop my clean-freakyness

)
So i think it can go both ways, really - the child isn't necessarily sponging off the child, and i mean, i'm my mom's only kid and i'm still her #1 priority. We're really good friends now and enjoy each others company, which was NOTTTTT true when i was a teen, so maybe we're kind of making up for lost time?
As for my kids, as long as they keep pulling straight A's they will get cars, a roof over their heads, and an education, spending money (school IS a job), help buying a house and me as a baby sitter whenever they need me. IF, however, they want to goof off instead they will get a place to live and no more, obviously the goal here is to improve their standard of living- not subsidize it.... but my grand kids will get the same contract as my own even if their parents turn out to be less than stellar. That's the contract.
This is the thing though. i do party and go out (maayybeee a little more than i should, lol), but i get myself up and go to work every morning, i clean our house when it needs it, and my room is in WAYYY better condition than my parent's room, hahaha. i like that part that i bolded - it's not that they're enabling me to be a lazy slacker, but they're giving me the opportunity to have a comfortable life when they didn't, and build the same for myself without the same struggle they faced.
I don't think it's a cultural thing totally. I sometimes think it's a spoiled thing mostly. I could absoutely state that I wouldn't date someone that was a professional but still lived at home at 26 or 27. That shouts dependent to me.
I'm not sure why someone in their mid 20s with a good job would want to live at home. I think it's because they don't want to have their lifestyle suffer. The person might have to live in a tiny apartment or even have a roommate. The person might not go out and about as much and may have to learn to cook and stay in. A 20 something at home doesn't pay the home bills and most don't even do their own laundry or clean up after themselves. I just think at some point a person needs to move out and be an independent person living on their own. You really learn alot about yourself when you are responsible for everything.
I'll never forget one time after college, a friend of mine was dating a guy that lived with his parents. For whatever reason, she ended up at his house. He still had his twin bed, with his kiddie sheets and his mom offered to make pancakes for his friend sleeping over. Needless to say that was the end of that relationship lol.
I am trying, VERY hard, to not be offended by that statement, that "most" of us don't even do our laundry, etc. That is an incredibly ignorant blanket statement for you to make, though i assume you probably know some people that make you think that, so fair enough, haha. But i assure you, i know LOTS of people who take care of their own bills, their own personal belongings, and pay rent, all while living at home; in fact, i'd say MOST of them.
i agree with you on the other parts though. Living at home past, say, 27 or 28 is definitely a red flag if they have nothing else going on in their lives, and no other extenuating circumstances, because it does make it seem like they're not ready to let go of being a child to their parents (and there's the weird, icky sex thing). And a twin bed? EEWWWWW no excuse after age 16, hhahahahha.
And i also think everyone should live on their own, if at least for a little while - the same way that i think that it should be required of all American citizens to wait tables for a year of their lives.

Definitely good life experiences!!
I think there's defiantely a difference between a person who is lazing around going nowhere in life on thier parents dime and one who has plans and is staying home to facilitate those plans. If the parents are ok with it, I guess I don't see why anyone would judge that or decide that a person is "dependant" or "spoiled" just becuase they don't make the same choices you would

. Saving for a house rather than squandering on an apartment is not spoiled, in my book.
Well said.