Moto has a reputation for being slow when it comes to rolling out Android updates. I have the Moto G4 Play and I am still awaiting the promised Android Nougat update, despite Nougat being released in August, 2016. In addition, I got the August 2017 Android critical security update a few weeks ago, so about 3 months after it was released.
That said, this is an issue for most non-Google Android phone manufacturers and comes with the territory if you buy a non-Google or non-Samsung flagship phone.
By the way, I do like the (G4 Play) phone and think it was a good value for the price.