I'm going to go ahead and guess that the flatiron school is not teaching much in the way of linear algebra or discrete mathematics, for example. That may not be a hindrance in many software jobs, probably most, but both are absolutely essential to the things I do day-to-day. I have met precious few developers who majored in something other than CS and can really grok a lot of the stuff I work on, simply because they don't have the education.
The exception is people who've taken the time to flesh out their knowledge with online classes from sources like Coursera. This gave them nothing comparable to a degree or completion of an educational program. They just took one class, and it wasn't even 12 weeks long. But that one class still provided enormous value.
The other exception is people who did attend a college-level CS program, but didn't complete it for whatever reason - dropped out, switched majors, whatever. They didn't get that BS in CS, but they still got a lot of value and were able to do something with it.
Granted, my calculations were dumb. I took the 4.3 years the article used as time to finish a 4-year degree and multiplied it by 52. Obviously, the number of actual weeks in-class is different, but I'd imagine most universities costs during the various breaks and lighter summer sessions aren't substantially less than in the middle of a fall or spring semester.