I always assumed having missiles behave like this would have some neat advantages (harder to shoot down, harder to predict the intended target, harder to automa

I always assumed having missiles behave like this would have some neat advantages (harder to shoot down, harder to predict the intended target, harder to automatically trace back to the launcher, etc.) and that the only reason real missiles didn't typically do it was the complexity of making sure they didn't hit each other or something else sitting outside of the shortest path. It seems like it could be done, e.g. pre-program all of the missiles with randomized paths that didn't intersect, and sweep the entire potential flight path area with radar or similar and exclude volumes with obstructions. That really is an awful lot of complexity that could make things go wrong, though.