I wouldn’t have been able to name the songs as a kid, even if I knew them. For example, growing up listening to my parents’ radio, I already loved the Beatles, Steely Dan, the Doobie Brothers, etc. - I could sing a lot of their songs, but didn’t have the connection to the artists in my brain yet. I just knew, “Oh hey, it’s that song I like.” Only when I got older and started building my own music collection did I start to connect the musician names and song names to the songs.

I wouldn’t be surprised if that were the case for kids in band T-shirts. Their parents bought them the shirt. Their parents probably play that musician’s music around their kid. The kid can like the music, wear the shirt, but still be unable to “name three songs” by the artist just because that information hasn’t come together for them yet.