I understand there is a limit of 65k tracks, or fewer, depending on metadata. I understand Sonos is extremely unlikely to ever overcome this, that the users who are annoyed by this are a small minority, etc.
My question is just curiosity (with little practical implication as the limit is unlikely to change): why? I understand the limit has to do with speakers indexing the music collection, but why on Earth do speakers need to index my music? Shouldn't that index reside only on the devices which control the music being played (computer, phone, tablet), rather than on the speakers, too? I see many downsides in storing a copy on the speakers, this limit being one, but I can't see many upsides. Indeed, AFAIK Sonos' competitors do not use this system and do not have this limit.