Personally I’m ok with discord for private social communication, imo not everything needs to be archived or searchable. But there’s people/devs who use discord as a knowledge repository and that’s the recipe for disaster imo.
The recipe: Old problem questions, solutions, how to guides, … All hidden behind a login wall and if you do get in, then you still have to contend with the crappy search engine, so you might just as well ask the probably already answered question yet again. And one day it’s probably all going poof or behind some kind of paywall. Basically also what quora has been trying to do for years, but I don’t think any people with more than a few braincells complain about quora being hard to access, since most of their content stinks anyhow.
Hitler’s flak towers are not going anywhere. There’s other 20th century buildings which can last a thousand years with occasional maintenance, but those flak towers, nothing will take them down.
Most very old buildings that survived to this age, survived because the locals had a use for them and maintained them, or because they had a pyramidical shape. The colloseum was a castle, the parthenon a church, … Without that usage, we’d only have the foundations and a few basements left.