Yeah, you are right.True. But they also made it seem as though they weren't even researching improvements for Mach. Like Dead Heat was it, even though they still had Formula waiting for Drive.
Now, correct me if I'm remembering wrong, but didn't they imply that Gou also went to Japan with the belt before the Mach System was entirely completed/tested?
It's probably a moot point now that Rinna made Chaser and all, but it's something to consider too.