Right, but an 18 year old facing large tuition bills is hardly in the position to be self supporting.
I think "financial independence" at such an age is overrated, I'll explain this statement in a second. My family is pretty tight knit, as such, our finances are similarly tied. If I make money, the "family" makes money; if my net worth increases, my "family's" net worth increases.
Conversely, if I spend six years to get a BS degree, have to work in the process, pay for a junk car to get around, etc... all in the name of "financial independence" such a situation can be negative for the family. This is not to undermine anyone who has faced such a situation, but it's well documented that those that are "poor" generally pay more for things (see recent Washington Post article).
Think about it...you'll end up paying in repairs/lost time for that car; if you live in a cheap apartment, you waste time doing laundry at a laundromat; spending 6 years to get a degree that takes 4 costs you 2 years of salary as an opportunity cost. Things just cost more over time when you have to lower your daily/monthly costs...like getting a 30yr vs. a 15yr mortgage, or moving to a cheaper location and commuting, you end up spending what you saved on gas/vehicle wear and tear.
Tying this together, because it costs you more money, it costs the family more money. If your parents are sitting on a pile of cash or are generally able to help you out, why not take it? You avoid the increased costs that "going independent" entails.
I understand the issue with the potential for spoiling kids and bailing them out well into their mature careers, but when done correctly, I think parental help can be constructive and money-saving for everyone.