Innovation in ANYTHING is rare. Most inventions are improvements on the existing ones.
I agree. The gist of my argument is that when smartphones first became popular, many new features were "disruptive" and not just incremental upgrades. High quality operating systems, amazing screen quality, powerful energy efficient mobile processors, multi-touch screen, dual tasking, great browsers, non-potato cameras, and etc. These features literally changed the world. People still expect Samsung and Apple to reinvent the wheel with each and every phone they release. But as technology progresses there is less and less disruptive innovation until another break though occurs. I.e. New cameras keep getting better and better, but aren't disruptive now like when smartphones killed the point and shoot. Maybe if they figure out to cram DSLR tech into a thin smartphone...
The point is that there is significant room for improvement in many aspects.
I hear, but I think: flagship phone + good network + wifi calling has us pretty much covered with not much room for improvement from the phone side of things. It's silly to expect my phone to have coverage in a Faraday cage even with future tech advancements. Theoretical max download speeds on any flagship phone are typically far higher than what any network offer. Networks can and will always get better and the flagships will continue adding LTE/5G/misc. bands to accommodate those network upgrades. Any innovation in this space has to come from the networks, IMO.