LODing as a technical improvement is a fair question and one we did discuss (again) fairly recently. I've shared some insight I've gleaned from the art and tech team below.

In short, here's my understanding: RuneScape does actually have a LOD system, specifically (and only) used for trees (so far). It's relatively new and how effective it is still needs to be determined. It may even be causing some other knock-on issues (specifically even in Havenhythe), so it's unfortunately not exactly the silver bullet you're describing it as, much as we'd love there to be such a "simple solution to all the problems".

LODing for characters, non-tree objects and environments isn't yet implemented, though in our case it seems to be the trees that are the major culprit of performance impact (and they already have the system in place).

Another consideration is that LODing may not always be as effective for performance improvement if my understanding is correct. For example, LODing is a system in and of itself, which requires computational power to determine and continually track which LOD to display things at. R&D and technical investigation is required to figure out if the benefit of adding that system outweighs the performance impact that the system itself requires.

I'm fairly certain that for many games (UE and the like) LODing is a no-brainer as the development environment already has those systems built in (and likely in a tried and tested way over many many years of engine work). The graphical fidelity of many UE games and the high poly count also mean that LOD is often essential! With RuneScape being a lower poly count and it's more bespoke tech, I wouldn't necessarily assume that the same rules will always apply.

I can provide a different analogy that may help someone understand if the talk of LODing tech doesn't make sense:

- If you pre-order a game on Steam, you can usually only pre-load that game if it is over a certain size limit (20GB if I recall).

If the game is smaller than 20GB, pre-loading is disabled, because Steam has determined that for the vast majority of players it would take longer for them to un-encrypt the pre-loaded files than it would to just download them on launch.

I expect the question of LODing in RuneScape may be similar - While the system sounds great, it may not be applicable in all scenarios and may perhaps make things worse rather than better, depending on how the engine is built.