A popular tech blog claims to have gotten the word from Motorola that its latest major release, the Moto Z4, may only get 1 full Android version update during its life cycle. Therefore, the new phone will see Q, but could miss out on R. On the other hand, the OEM also pledges to support the device with 2 years' worth of security updates.
https://www.notebookcheck.net/Looking-forward-to-Android-R-on-the-Moto-Z4-Don-t-count-on-it.425069.0.html