First rule of marking. Say your name, loud & proud! Bragging doesn't take care of itself. Gotta be like the Beastie Boys, say your name 3+ times in every song.
The only tech merch I've ever worn was back when firefox had a good logo, goodwill, and no text on the front of the shirt.
Lots of people just want a simple graphic tee and IFKYK. It's not sports. Bands can sometimes get exceptions, but often approach wrestling tshirt levels of gaudiness.