I've used iPhones since the 3gs, and the iPhone 8 allows me to be more productive than any modern phone (had the Samsung S4, s5 and an early Google nexus device) I've owned since the blackberry.

I'm sure iOS 12 will slow it down, but for now I feel like my productivity is finally getting back to Blackberry days. My nostalgia for the instant response of those devices has grown over the past few years as phone os's and apps have become increasingly bloated. I really think there'd be a market for an email / messaging only device intended to be carried along side a phone if it did that one thing very well.