Yeah, it's gonna stay as 16/64/128 for at least another year. Apple probably won't make the base model 32GB until all of the other competitors are doing it, unfortunately. Their strategy definitely got a bunch more people to get the $299 model this time around, me included.
I'm actually wondering if we'll see an iPhone based on Cloud storage soon? I know it's unlikely, but given the push toward iCloud (and cloud-based storage in general), I can see Apple doing it. For example, if they were to do this with the iPhone 7... All iPhone 7 models have 32GB of on-board storage. However, the $199 model would come with 16GB of iCloud storage, $299 model would come with 64GB of iCloud storage, etc...
It wouldn't work with the current iCloud subscription model, but I wouldn't be entirely surprised if Apple went this route. I prefer on-board storage anyway.