It totally would have been normal to have a custom shirt like that back in the day. I had a few.

In the late 70s and early 80s, there were custom "iron on" T-Shirt shops in most malls. They would have a wall of larger iron-on decals, primarily logos of sports teams and rock bands, but they also had custom letters, usually in the Cooper typeface. You'd tell them what you wanted, the size and color of your shirt and lettering, and they'd go in the back room and iron what you wanted on your new shirt for a few dollars. This was especially popular with youth sports teams in lieu of professional uniforms, families who wanted to match for a big trip (often with custom names like this), and, as you can see here, jokey custom workplace team shirts.

If you watch a late-70s or early-80s episode of The Price is Right, you'll almost certainly see contestants or audience members in these custom iron-on shirts - same font, same slightly disjointed look.

The left-hand text on Dave Compton's shirt is slightly blurry and unreadable given the resolution, not garbled. But it's not some AI nonsense.

DAVE

COMPTON

(King?) OF PACKERS

(He'll?) PUT IT IN ANY BOX

This isn't just a rah-rah team spirit shirt or something obscure, it's a peculiarly '70s innuendo combining thoughts about his job... and his sexual prowess. Sure, that kind of shirt would cause a modern workplace to, uh, send him packing. As they say, it was a different time.

Here's a thread on Reddit about one of those mall custom iron-on t-shirt shops: https://www.reddit.com/r/70sdesign/comments/hf6f0q/tshirt_ir...