My three siblings (27, 24, 18) still live at home and are subsidised by our parents. I'm the odd one out for not remaining in the family home, haha.
My parents can definitely afford it, though they're charging the eldest two rent. Even with having to pay board my brother and sister are making out like bandits, I bet their savings rate is way higher than mine purely because mum and dad take care of them.
I do worry about my siblings, because if my parents financial or physical situation rapidly deteriorated they would all be in for a huge shock. Sometimes I wonder if my sibs development as adults has been stunted because my parents do all the real "adulting" in the house (bill payment, grocery shopping, laundry, yard work, etc). Luckily my parents tell the older two to fund their superannuation, save and invest, but I don't think they feel any pressing need to worry about it like I do.
That said, my parents are doing far better than a member of my extended family, who continually has to bail his kids out of whatever stupid decision they've made this time. He knows it's a problem, but in the moment he gets sucked into their swirling vortex of self-inflicted drama.
So yeah, it works well in some situations but in others it's just enabling.