I don't know if the author knows anyone who is an artist, but if they knew an artist it might add perspective on the t-shirt. There is a type of person who is driven to express their ideas and emotions. They can be moody and quiet or loud and extroverted but they get consumed by the process of creation and go into something like a trance state while creating. I have been that type of person and when I let myself go,…
I think something that needs to be discussed then is not to exclude the spigot people from the hiring process just because they aren't driven to create like you are. Unfortunately, it comes across as attacking you, the creation types while it should be attacking employers who think Mr. or Ms. or Mrs. spigot would be a worse worker than you.
This has always been a challenge for me (and at this point I suspect always will). I don't know exactly how I come up with the stuff I do, it just sort of pops into my head. More rigorous people who can write down a series of milestones and check points are great at giving visibility into the process. My workaround has been to work with good project managers when I can and talk to them about what I know and don't know about a project. The "don't knows" become future deliverables, the "knows" become steps that can be done now and shown as progress.
Looking back on my career I have been the most successful in a group which is a mix of types, call them artists and engineers. There is probably a management book out there somewhere that addresses that question.
[1] Or "constructively criticized" using the Intel vernacular.