Why isn't land in a 3D world sold in 3D?

Would solve a few issues with banlines and adfarms but create a few I guess too.
But wouldn't make sense to buy land by the cubic metre, maybe in 20m or 50m pieces vertically so if you wanted sky you brought a cube up there.

How would that go with land permissions for example?

Seems quite impractical to me in more ways then just permissions. One sim has a given amount of prims to divide, would they seperate sky parcels from ground parcels, the amount of allocated prims would split in half.

Plus one would not be able to fly over their own land, or build a high tower. You can think of more I bet

Hmmm, so, if I buy a parcel from 0 to 500m then someone else could buy from 500 - 1500 and park a prim sucking, particle spewing, lag scripted, resource hogging sex club on top of my house?

After 30 some odd thousand years, we still buy land on a 3D world as if it were 2D; and this is on a sephre. At least The Grid™ is flat.

Almost all the land management features in SL were designed with no concept that anyone would ever build or interact anywhere but on the ground. The designers may have envisioned people flying, but they never took into account the idea of actually building stuff in the sky.

Server resource allocations are all based on that 2d model, so there is no way, at this time, to partition a parcel vertically. I'd LOVE to be able to specify a 3D permissions zone for access privileges. For example, to specify that the only places that my access list and ban lines affect is a small area on the ground, and an area around my skybox. Or just at the skybox, for that matter. Instead, I can only set up general access controls in a layer that hugs the terrain, to 50 M above the terrain. That is less than 1.22% of the volume of my land's airspace, in the buildable range to 4096 Meters.

Sims don't have enough resources to sell land in a stacked model. If a 2D 512 m2 parcel only allocates 117 prims in that parcel's airspace, dividing that into 4 vertical parcels of 1024 M2 of altitude each would have to divide that allocation by 4 as well! Would anyone other than an ad farmer pay for a 512 M2 parcel that only allowed you to use 29 prims on your land? I don't think so.

I bought my land and got the sky for free. In both SL and RL. It don't bug me much at all. (^_^)

My little piece of pride is the basement I have... Because of the odd build of the area, I get that opportunity and it makes for a nice hiding/meeting/gathering place in ways that a skybox can't accomplish. (^_^)y

I support the idea of landowners being able to vertically subdivide their plots for permissions / rental / music stream etc. but would not want it to be possible to sell vertically subdivided plots separately.

I'm trying to build a skybox in RL...

Anybody got any tips? I'm struggling with the gravity thing ATM

To avoid drifting into the neighbor's airspace, try an altitude of 35,784,000m.

The moment I know I could have neighbours ABOVE me is the moment I sell my land holdings and leave SL. So would a majority of people who own land. I use my "sky" as a major residence. In terms of land ownership, SL actually follows the real world. It is an ancient law of "lights" - building permissions are extremelly complex in cities where obstruction of light can be a major factor in a development. I think SL are wise to avoid this issue here.

The servers couldn't handle the prim usage if we started stacking property. For every layer, you double the number of prims that you allow in the region. Either that or you reduce the number available for each plot, which would be awful - I don't have enough as it is. If I had to split them with my neighbors above or below be, I'd have to live in a box maybe I could afford one of Marcel's low prim chairs to sit on if I was lucky.

Since I build in sky personally I would prefer to raise the ban lines myself.
I guess one solution to getting rid of band lines is having security orbs...maybe I will get one of those.

Well, yes there would be more prims per sim but I suspect there may be a lot less sims required too as a server instead of doing 4 sims would run just 1
Well at least if an adfarmer ownly owned the 50m at ground level they couldn't follow you with a 4000m temp rezzer and particle beam