This gives me an idea for recycling the powered down worlds into "new" worlds for new users. Being able to see and use the abandoned bases of past players would be quite fun.
You could take this a step further by "decaying" the bases in some way (remove torches, remove some large percent of the items in chests, add vines, weather rock, move blocks from the ceiling to the floor, etc)
At least the issue with that years ago was when minecraft would have an update that introduced some new generated resource where you would have to get to the edge of the map to generate some to use. Most servers restart periodically to get fresh resources near spawn, not only for new resources that might have come out in recent updates, but just because the area has been completely harvested by past players like some scarred piece of land and you need to start venturing out far to find trees or ore.
Is there a mod that gradually adds new resources to old worlds, gradually adds ores back to their gaps in caves, gradually restores the environment, as well as gradually removing torches and “decaying” old structures?
Otherwise someone should make one. No need to full reset servers any more.
I think some servers do "chunk resets". The idea is to take chunks with little or no player activity and delete them so they'll be regenerated next time someone comes along. I think I've heard of this being done automatically (chunks that a player hasn't been to in X days will be deleted). It would lead to a discontinuous world though, with older chunks having sharp borders with newer chunks that aren't even the same biome.
This is great idea, but may be tricky as people often just mess around with the world. You would need to, somehow, decide which abandoned base is visually appealing and/or matches the environment.
If my memory serves me correctly, it is rather easy to decouple natural from player made blocks. It was either stored separately on storage or at worst you can deduce it by "subtracting" a fresh chunk generated from the seed.
Then you just need a good heuristic to guess whether or not a group of blocks matches your definition of a base to be explored.
You could take this a step further; once you have determined that a set of chunks have been modified significantly, you could apply that set of changes to the same coordinates of any map generated from that seed, meaning you can combine changes from multiple worlds into one (with the same seed).
Fwiw, there are public servers that have been running for a decade now that have a similar effect. The world is chock full of player content just sitting around waiting to be rediscovered.
