That is unfortunate, although I guess I can understand. With Shareflow, Zenbe may just have a different vision for it than I do, and it might not be an easy change. They have to prioritize their work, I guess.
With Gmail, I have no idea how big a project that would be to do non-threaded emails. The threading has its hooks into other features, like labeling, so I guess it could be more work and resources than we think.