I have never been able to find evidence that the 25% of the population made up of those with degrees fare better than the top 25% of the population without degrees. But since we are going on gut feelings here, my gut tells me that you will find no discernible difference between the two groups.
In my experience in the UK it really depends on what you are applying for, here the biggest companies tend to pay the best salaries and the biggest companies don't tend to like (for example) self taught developers.
If you look at job listings here for programmers a degree will be a requirement for more than 50% and they won't waive this because you have an impressive github.
Another big plus for having a degree is that it makes getting a VISA easier thus giving more options. Also there is also the advantage that by being in college/uni you will meet people who have the "right background" which can help in job search.
For example the father of one student in our CS class asked his son to tell him who the best 10 programmers in that year were and more or less hired them on the spot at graduation.
What I am saying in essence though is not "get a degree" vs "don't get a degree" but rather that saying "don't get a degree because you will be $X richer in 4 years time" seems like a rather weak argument.
Since I am not familiar with the employment landscape in the UK, I am going to have to take your word for the satiation there. However, since this article is US-based, I do not feel that your picture paints the employment situation in the US in the proper light. Formal education does not have that kind of relevance on the western side of the pond.
A few points come to mind: (1) Access to money makes going to school and finding work easier. (2) A "go-getting" attitude makes successful completion of college and finding work easier. (3) Living in the right location (namely cities) makes going to college and finding work easier. (4) Simply being lucky makes the successful competition of college and finding work easier.
If you could find two people who are exactly equal in every single way, except the piece of paper in hand, would you find any employability differences between them? I'm highly skeptical that you would.
I would wager that you are more likely to get a job as a graduate that will provide you with useful experience.
A huge number of non grad jobs don't pay too bad by the standards of a younger person but really don't give the sorts of experience that help one get ahead.
I know smart people who skipped college to work retail and 10 years on are still pulling not much more than minimum wage. With a reasonable degree they would certainly have had more options open to them.