If true, here's another example of why it's a good idea for Samsung to be testing out a first generation product like this with only one device:
Why the Galaxy Note 4 Still Doesn't Have Android 5.0 Lollipop. It seems reasonable that it is true considering that Samsung usually updates their current generation flagships first, but the Note 3 recently began receiving the Lollipop update internationally before the Note 4.
After you translate the article, it says that Samsung is delaying 5.0 for the Note 4 because Oculus is having issues with the Gear VR software on 5.0. If Samsung was supporting multiple devices for the Gear VR, this would be a problem that would cause much of their recent lineup to see delays in getting 5.0 or if they went ahead and updated without fixing things, they'd have to deal with bad press and ticked off Gear VR customers (with the bad press being the bigger issue of the two given the limited number of Gear VR customers).