Because of the nature of federation posts and comments on LemmyNSFW communities will live on basically forever. However the photos and videos will likely be lost. Some were links to external media and will stick around, some may be cached. But most photos and videos that were uploaded directly to the instance will break when the server fully goes down.
For example: [NSFW, OBVIOUSLY] [email protected] - that link should load fine on your instance. It should look functional just with no new posts. (Note: it’s actually possible to post and comment in these communities still, but only people in your instance will see it)
The images are served from links like these: (mild NSFW) https://lemmynsfw.com/pictrs/image/d50379d3-7d64-440c-bcf6-13dbf2b81c1b.webp?format=webp
The fact that the images still load is a somewhat hopeful sign. The server is still running, Lemmy just crashed. There’s still time for the head admin to come back, the data still exists. This seems unlikely though as the other admin says they haven’t heard from them since October.
So there’s a small window to archive this stuff, if you’re interested. Between now and whenever the media server crashes or gets shut off for non-payment.
Oh yea, I actually considered trying to run a replacement for a time, I’m still running the stack I setup for it but I decided to stop pursuing ‘productizing’ it and moved on. That stack just became my over-engineered personal instances - https://bestiver.se/
I setup a stack of Lemmy+Mastodon+Linkstack on subdomains, with the intention of selling accounts to people who would benefit from fully controlling their own social media presence…including adult creators. Afterall, they can’t get kicked off of something catering to them. I even setup a shortlink thing like: https://bestiver.se/@patrick
I still have the domain “xxxiver.se”
If you’re wondering why there aren’t other instances catering to that, it’s because hosting that content is expensive (lots of images/video content), time consuming (tons of mod reports), legally problematic (you better respond to mod reports/police inquiries quickly), and there is no simple way to accept payments since everything kicks you off if they know it’s porn related.
I think your other big problem would’ve been that attempting to “productize” it (beyond asking for donations to help with costs), would immediately make everybody else on the fediverse hate you.