The biggest fallacy with this, and with what I am assuming it is based off of, is that it assumes you have all that money right now. If you have all that money at age 18, then obviously you have a job or personal business that makes you enough money that you don't have to go school. You are starting off pretty well.

Now realistically you will not have that money at age 18 when you are making a decision on college. I am in college right now, I have scholarships, financial aid, some loans, and am working. So to say well just invest all that money and dont go to school, is easier said than done, because I do not have all that money ready upfront, and I highly doubt that a majority of students have that type of money upfront. I am paying as I go, and that is what most students do. You pay a semester at a time, not all four years upfront.

The whole thing is based on an 18 year old having 150k, which I think is very unrealistic. So the point can be made that yea you would have more money, but you also started off in a position where you have alot of money, since that is 150k of disposable money, spendable cash, aside from the cost of living.