I disagree with this opinion, strongly. I think that the fact that he has considered this enough to ask the question at the relatively young age of 23 is a good sign. For me, at 23, all I cared about was how much I was earning that year, and I didn't give much thought to the prospect of having...
The most realistic way to make enough money to retire 20 years early is to start a business and build it to something sellable in 10-15 years. Don't be too tempted to start a business doing something that you enjoy doing, as chances are that lots of other people will enjoy doing it, and you'll...