You're correct, there might be a text-mode fallback. It's just that it is effectively useless for me. If I don't have network access, how am I going to install

You're correct, there might be a text-mode fallback. It's just that it is effectively useless for me. If I don't have network access, how am I going to install the firmware for the network card? That's why I believe the most common firmware .deb packages should be cached during installation so that they are on-disk in case they are needed.