This is not a problem with SL, because SL, like most 3d games was designed for low poly 3D meshes. If you are under the impression that you can just download any high poly mesh from the internet and upload it to sl you are seriously mistaken.

If you download a mesh like that you will have to open it in a 3d program first, blender for example, then simplify the mesh and optimize it as a low poly 3d mesh before uploading to sl, and if you don't know how to do that you shouldn't upload anything at all.

There are tons of free tutorials that teach 3d modeling.

if land impact is that high then this is a bad model to be using even in platforms such as SL which is a streaming platform. It looks like this model is almost 90mb before any of textures and that doesnt include physics models which is likly where alot of the land impact increase is coming from. You would need to optimize this model for us in SL. (or even some other realtime rendering scenarios/engines)

Hello, and thank you for your detailed post regarding mesh land impact. We understand how frustrating it can be to manage land impact with high-poly meshes, especially for large structures like ships and buildings. This issue has been brought up before by another resident in Second Life's previous bug tracking system (BUG-232698). We are merging your comments with the existing report to help us address it more efficiently. While we don't have an estimate on when this might be resolved, please keep an eye on future updates. Your input is invaluable, and we appreciate your commitment to improving Second Life. Thank you!