The internet’s best resources are almost universally volunteer run and donation based, like Wikipedia and The Internet Archive. Every time a great resource is accidentally created by a for-profit company, it is eventually destroyed, like Flickr and Google Reader. Reddit could be what Usenet was supposed to be, a hub of internet-wide discussion on every topic imaginable, if it wasn’t also a private company forced to come up with a credible plan to make hosting discussions sound in any way like a profitable venture.
my opinion: the knowledge is not going to “lost”, cause niche community probably will crawl their own data or reddit wiki/FAQs before they retreat to other platform, lemmy or not. However, that also means you can’t just google the phrase and put site:reddit in the search term to quickly filter your results.
Yes it sucks that say in the future you want to search for something it would take more time to reach the same result or user base, it will still exist somewhere. Like those emulator or homebrew communities that are universally chased/DMCAed around the internet, they still exist and you just need to spend more time to find them.
It’s not just spending more time though. If they splinter out into the fediverse, that’s not too bad, but the major downside of independent forums was that you needed to register an account for every single niche and obscure site, many of which had restrictions and weird requirements for registration, posting, and participation, and generally had a far less reach than reddit.
Reddit is just one account for everything. Technically, the fediverse can be this, but then, the pitfall here is the volatility of instances. What happens when an operator decides they can’t manage it anymore? Or they’re situation changes and they can’t afford to? Or they pass away? Or any number of scenarios? Sure, you can just re-register in another instance, but whatever information had accumulated in that instance is now blackholed. It’s just gone.
Reddit won’t likely go out completely any time soon, and the wealth of existing knowledge will continue to be reachable, but it will become continually less useful for new queries. Now there’s an empty space.
If Lemmy wants to fill that space, it’s volatility needs to be addressed. I’ve mentioned this before, but I think the simplest way to address this would be to implement mirror instances, with the sole purpose of being a real-time redundancy for other instances in case they go down.