The thing is that the PC and the stereo were often in different rooms. That was the case for me where my stereo system was in the living room and the computer was in the second bedroom of my apartment. Remember that home networking, wifi and “spare” computers were also not really a thing in 1999 or before either.
I remember getting 25 foot cables, but I know I'm definitely in the minority, my dad worked as a telephone installer, and loved setting up audio systems so I had a bit extra access to the cabling stuff.
When I got my first high-speed internet and bought a 4x1 ethernet router/switch, I remember wondering what else I could network since I only had two computers to connect. I really wanted to somehow connect to the music gear in the main bedroom, but I never did.
