> It was a complete failure. That branch was abandoned and development continued off the spaghetti.

It was considered too hard, most likely because the present state of the code already degenerated beyond recovery. It might be difficult, but it's never impossible.

> Mapping to terrain is always the real effort in my opinion.

Yes. The domain might be complex, and it might be possible that there are no simple ways to work within that domain. Irreducible complexity is, after all, a thing.