Sounds like nissan has no idea what it's going to do with the next Z. They want the entry level sports car, the Z sports car and the supercar in their lineup. It's actually smarter if the idX is the lowest tier in the Z setup and the Z is the highest, kind of like how their is a impreza then wrx then STi. But if the idX and Z are 2 different platforms and if the next Z doesn't do well its definitely getting the axe lol.
btw lot of 'interesting' comments in the jalopnik article
http://jalopnik.com/the-next-nissan-...e-m-1643094196