The naming is a bit annoying, but they are completely different kinds of thing: AVI is a container format (which can contain a variety of different codecs, e.g. mpeg-4), and AV1 is a codec (which can be put in a variety of different container formats, e.g. mp4). We don't seem to get confused between mpeg-4 and mp4, which have the same kind of similarity.
FWIW, I never noticed the connection until now. I guess AVI has been 'gone' for too long, and it's not in most people's minds anymore.