The risk is in thinking you’re building one when you’re not. T-shirt worthy brands are a very small subset of the whole.
If you’re creating identity, possibility, connection and giving folks status, it’s easy to see how you could build a t-shirt brand in just about any field. Sports teams do it for a living. Google had a t-shirt brand for a long time, and so does Penguin Magic and even Festool. I’m not sure, though, that many people want a t-shirt from BMO bank, Marriott or International Paper. Netflix might be, Roku isn’t. Of course, no t-shirt brand is for everyone, that’s part of the point.
If you’re simply providing a good service at a good price, perhaps you don’t need to go to all those meetings and waste so much time and money on “branding.”
Why would someone want to wear your name around town? What’s in it for them? Go build that and the t-shirts will take care of themselves.