I had a similar experience when I went to see James Blake; the audience was bimodal in age and there was a younger crowd that only knew a few of his singles that had gotten real big (collabs w/ Travis Scott and Rosalia)

So maybe this is normal as we get older? I didn't know this had happened with Alex G but I'm happy to hear about his success -- to me that's the main thing that matters, however an artist finds their audience.