Exactly this. An example is ipv6. ipv6 was created in the 1990's and was expected to replace ipv4 by the early 2000's. It's 2020 and deployment is about 33%,

Exactly this. An example is ipv6. ipv6 was created in the 1990's and was expected to replace ipv4 by the early 2000's. It's 2020 and deployment is about 33%, most of that being mobile devices. People move slow unless something forces them to change.