PS: Granted, not a scientific study but my sample size is over 30 and the difference is fairly dramatic.
The mechanical engineer would have a better time. It's one of the reasons vocational/on-the-job educated people end up with lower wages; generally educated people can go where the money is.
This is slightly complicated by the fact that people going to well-known colleges get a head start on the network. A decent education on its own has more dubious value. Most companies want experience. I know that when I evaluate someone, relevant experience is way more important than if or where they went to college.
That's what a general education in the subject is for.
Thats not a win at all, its a loss.
Experience relies heavily on ones own bias judgement. It can also lead to doing things without understanding them (i.e. writing shit code that works vs. writing good and efficient code) and can lead to nasty habits. Experience is also a slow teacher.
College is advantageous is that you are taught why things are by an experienced individual. You are able to gain a fundamental knowledge base and terminology that can be applied rather than wasting time being taught on-the-job. Plus you are taught things that won't and can't work in your field and why. All a person with experience can tell you is that they won't work and give some superficial reason why. Thus, the experienced person opens a book and has to acquire fundamental knowledge that they could have learn in uni.