The VX is hub centric, and it isn't that old....yet. I would think Isuzu did it for a good reason. That's all.
Actually I don't think it is. If you have hub centric rims, you will NOT have conical lug nuts. I think the factory rims are just a relatively close fit to the hub which is not neccesarily hub centric. That's all I've got to say about that.