5G is not a single feature that you either have or don’t have, it is an evolution from 4G involving many new capabilities and applications that are all on separate schedules 
 

Each carrier implements 5G somewhat differently (bands, services) so it’s really more of a large and varied set of standards delivered on a continuous rollout schedule with individual implementations
 

5G hopes to accommodate the Internet of Things (IoT) including mobile data and voice, but to do so:

          1.  It requires a huge increase (‘density’) in ‘nodes’ to which devices can connect to the internet, and;

          2.  Those nodes must have higher than normal frequencies to handle the data required, and;

          3.  Mobile/Data carriers must maximize the ‘efficiency’ of those nodes to be competitive, and;

          4.  Those nodes must ‘backhaul’ to an ‘internet line’ (IP) in order to transmit and access data, and;

          5.  The ‘fronthaul’ part of the network that connects to mobile devices must be standardized, and;

          6.  The network must have permitted places/nodes for the radios, and reliable power for them.