I liked waytoomuchstuff's classification. I consider myself to include all three, with less of the hobbyist component than the other two. I suppose if either of the first two factors outweigh the third in a listener, that would lead to continual changing of gear.
I suppose if I had extra gear as good as what's in my main system, I might be inclined to swap things occasionally. But I don't, and it would be a big undertaking. I'd rather just enjoy my system, which is quite satisfactory as it is. I could certainly see an audiophile having a pair of speakers that is best for chamber music and another that is best for rock, and swapping those, which would perhaps call for changing the amps as well to best match the speakers.
I suspect that sort of gear-swapping is different from buying new gear, which involves the dopamine excitement that bigtwin correctly mentioned. I get that effect myself from buying music-making gear; I suppose if I wasn't a musician, maybe I would spend the money on new audio-reproduction gear instead.
For me, after assembling a musically-satisfying system, I don't get bored with its sound, but I seek to listen to different music. I would get bored if I couldn't find new music to sample. Streaming and a few radio programs are very helpful for that.