The problem with research like this, and in particular conclusions formulated along the lines of "it requires being in a state of flow to be a successful photographer", is that it tends to be oxymoronic or tautological. It's not a matter of 'getting yourself in a state of flow' and then success as a photographer will ensue. The reverse is actually probably more likely - that the sense of being successful enforces that feeling of satisfaction that apparently coalesces with this 'state of flow'.
This is apart from other grave conceptual problems, such as:
* Lack of an academically sound definition of the core concept; i.e. what 'flow' constitutes is likely influenced deeply by the different (dare I say, idiosyncratic) conceptions the respondents and the researchers have of the concept.
* Lack of emphasis, especially in the linked article, on confounding variables and otherwise relevant contextual variables.
* Lack of rigidity in demonstrating internal validity; i.e. making a convincing case that the supposed causality in reality holds true as portrayed in the research.
To put some of the above in more understandable language, I think this report fails to convince because a number of other things may be going on. For instance, there may be all sorts of factors that result in the same sense of being in that 'state of flow' (whatever the heck that means exactly) as well as career/business success. Think about having a solid education, good social network support, good social skills etc. that are rewarding in themselves and tend to contribute to professional performance.
If you strip off all the romantic and imprecise formulation, what you end up with in a story like this is a conclusion along the lines of "successful photographers experience job satisfaction". These are constructs (professional success, job satisfaction) that are at least measurable, are reasonably well-understood and conceptually distinct. But the conclusion is also one that adds no value whatsoever on top of what we have already known for many, many years.
My main qualm with an article like this is that ultimately, it doesn't help anyone. That there's such a thing as "flow" is nice, and it does have some academic relevance (I think there's some research in the area of creativity that has tried to give some substance to it). But 'knowing' that successful photographers experience this flow is practically almost meaningless. It's not going to help anyone to strive for that ill-defined sense of 'flow' in order to become a successful photographer.
At best, the reaction this article can then trigger is something like "well whaddayaknow" - and that's that.
Had they presented this as a blog or a column, I might have been less critical.
And I'm also very open to the very real possibility (perhaps even likelihood) that the actual research is pretty insightful - just that it's reported in a very informal manner in which all of its merits are lost.
Disclaimer: I've supervised, coached and assessed between 100 and 200 (honestly I never bothered to count) thesis students and/or their works, varying from bachelor's to PhD level, with a great variety of topics and an emphasis on qualitative research methods. Topics that I have dealt with in this context include for instance job satisfaction, creativity and entrepreneurship, although I consider none of these my specific expertise. This background has certainly heavily biased my response and probably has made me more critical than I ought to be, given the effort put into projects like these.