Flash will take over from HDD and hybrid systems, for all it's benefits, but it will take 2-4 years to get there. And of course it will not totally displace disk in all cases as we still see tape every now and then.
There is already considerable intelligence in the software stack, which increases endurance and performance, way above the figures quoted by the manufacturer. This means it reduces cost $/GB, $/IOPS and at some point it will not make sense to run disk. And only this year there will be a considerable amount of new functionality added to the data management software layers that will extend and the capabilities of the raw devices. As 3D XPoint/NVMe add new tiers of devices and software starts managing them intelligently there will be even more fine grained ways to address specific use cases.