It doesn't work.

Create three 4096x4096x24bit BMP textures a.bmp, b.bmp, c.bmp and assign the first two as new two skins to the marine.mdl and the third as new skin to the stone.mdl. Each texture is ~49MB big, so if they were streamed in the background, the boxes should appear first (since they are small in size), then the stone.mdl (approx. half as big as the marine.mdl then) and at last the marine.mdl because it's HUGE (~100 MB to load in one frame).

What happens if I run your example?

All entities are created ONCE in ONE frame. So, no multithreading, no streaming. It doesn't work as it should be.