Sure! I tried sub-contracting in Massachusetts for a guy who did Computer Repair. A lot of people/businesses used him and after some time started asking whether he could put together websites for them (you know, because all computer work is roughly the same). Well, he looked me up and I joined him as the web team.
I came on looking to expand on my development abilities, but I soon realized that very little of the is spent actually sitting and programming. There was meeting with customers, getting requirements, creating some sort of plan then figuring out how to break it all into a roadmap/schedule where the delivery is satisfactory and on the proper date. I had little to zero experience in any of those tasks.
I struggled to gain comfort during meetings and lacked confidence while I would be setting up the schedule, I assume it stemmed from my beginner status and an overall lack of successfully completed tasks to look back on (whether as a sub-contractor or just even hobby projects).
There were times I'd ask my father for advice (he had started a company that was rather successful), read a book or two, tried some online resources, but really, I was probably just too young and not wired to be a sub-contractor at that point in my life. Sometimes I do look back and see the mistakes I made and what I could have done to correct them, so in a way, it was a great learning experience - but not in the area that I wanted.
I've since done some "internships" (one where I was paid less than minimum wage and worked full days - but I really wanted a job experience) and realized that I came away with way more than I could have ever discerned from my experiences as a sub-contractor. However, I strongly believe this was due to the fact that I wasn't all that great development back then. Nowadays, I find that the business aspects come a lot easier now that my programming/development understanding are eons beyond what they were even 4-5 years ago.
I should also make certain to mention that my experiences are my own - I wouldn't be surprised if someone younger than I were thrust into that situation and would came out successful. However, given my past personal experience (and not even running my own business) I have to hesitate at the article's implication.
Anyway, I hope that was some good info - feel free to ask any questions if you'd like, I'll do my absolute best to answer.