The short answer is, we don't really know and won't hazard a guess. But the press release from T-post, the responsible party, tells us, "Subscribing to T-post is a lot like having a subscription to a magazine but instead of receiving magazines in your mailbox - you receive T-shirts." So then, not at all like subscribing to a magazine. The concept is that the designs on the chest are an interpretation of a current news story, which is summarized in text on the inside of the shirt, so that you can opine like landed gentry when some hapless sucker asks you just what the hell is on your shirt.
This particular issue, "De-evolution," cites a study that claims a third of people under 30 can't remember their own phone numbers and quotes New York Times
journalist Bob Brooks, who wrote, "I had thought that the magic of the information age was that it allowed us to know more, but then I realized the magic of the information age is that it allows us to know less." The design on the T-shirt is San Francisco-based illustrator Matt Furie's vision of the future of the human race. Evolutionary theorist Oliver Curry of the London School of Economics speculates inside the shirt that the human race will peak in the year 3,000, and then will eventually come to resemble something closer to domesticated animals cared for by their gadgets. He sounds like he'd be fun at parties, as we suppose T-post is intended to be.