>While I do think that was an exaggeration at the time, I worry about the loss of effort and 'thought-power' when the discord walls get even taller than they are now -- or worse yet -- when the gardens disappear without ever having had the chance to have been archived somewhere.

I use Discord a lot, and while I'm sympathetic to the concerns they're not relevant to the servers I frequent. Discord is so abysmal to search that anything that users want to share beyond chat/memes/pet pictures gets posted in the forum and linked to from the Discord. Any ordered discussion just falls apart in Discord, so every server I'm in either:

* Is small and ephemeral (Breaking rules, trying to not get the main server sanctioned)

* Is a private group where archival is undesirable

* Has a wiki/forum/dropbox/drive where conversation and artifacts are shared, organized and archived.

I don't think you're wrong about Discord being difficult to index, I just think the problem you're describing is, at worst, understood and has simple workarounds, or at best is an actual feature that people want.