So for a while I briefly worked the same company as Aaron Kambietz. During my time there, I asked him how the developers came to the conclusion to use a vertex-

So for a while I briefly worked the same company as Aaron Kambietz. During my time there, I asked him how the developers came to the conclusion to use a vertex-coloured skybox like they did in the article. If my memory serves, he said the primary reason was wanting to hit a particular memory budget for the appropriate minspec at the time. Or, they felt any memory dedicated to textures was better spent on the spaceships. The vertex data was hand-authored by the artists tracing over original artwork (I think on a Wacom-style tablet). He stressed that it was arduous work and took a few weeks!