There are a great many factors involved.
One is the particular field. To use the accounting example, now there is a field that is more or less mature. The skills wanted in an accounting position have been laid out, and innovations are not as frequent as they are in some other fields. The training to properly develop those skills has been integrated over many years into a more or less standard college curriculum. If accounting is what you were going for, why not get the degree? In general, for some fields, a school is the only practical palce to get hands on experience.
In the case of Bill Gates et. al., you have to remember that he got his start at a time when computers were only about 25 years old, and computer programming several years younger than that. There were precious few courses of study in the field in the mid-seventies, and many of them still regarded the entire field of Computer Science as simply an interesting elective subset of the study of Mathematics. So a degree wasn’t really necessary for him to do what he was doing.
That said, you may STILL want to go to a college if you are in a cutting-edge field, because that’s where all the new research is being done. It just may be harder to get in to a cutting-edge school.
It also depends on the job market. Back to accounting: You can swear on a stack of bibles that you have spent hours at the library learning everything there is to know about accounting, but if the hiring manager has 20 other applicants, all with degrees from nationally accredited institutions which have good reputations for producing quality workers, why should they look at you? But if your the only one in East Podunk who even knows what a spreadsheet looks like, you have an advantage without the degree.
There are also factors outside of the specific knowledge you gain. People who have spent four years away from their parents interacting socially and academically with their peers tend to have a very different way of dealing with the world than those who did not.
In some careers, you benefit more from having the degree, some benefit more from not being “overqualified”. A plumber with a degree in fluid mechanics does not have an advantage over one who does not, and both will probably make more than several other fields that require college education.
But enough theory. Fifteen years ago, I ended up in a situation where I could not finish my own degree, and found that the fields of interest to me generally required them. I have listened during that time to people my fields of interest who had degrees, started their careers when fewer companies required BAs of entry level workers, or otherwise never had to start at the bottom of today’s job world without the benefit of one claim that a degree was a totally unnecessary expense of time and money. My experience has shown me that they have no idea what they are talking about, and I am very grateful that I will be completeing my Bachelor’s in May.