As a sexagenarian (no jokes please), I can assure you it is more environment.
Age will tell you the general environments which affected the person. Older people tend to have more experience in less digital intense environments than younger people. If an older person stopped evolving their technology environment and its use somewhere along the way, then I'm sure that might lead to the conclusion that age is the cause.
However, corrolation is not causality. I believe the real cause is in that case is familiarity which can lead to not adopting newer environments for some people. For other people who adopt new technology easily and adapt to constant change, they will continue to be right there with the best of their younger peers and, perhaps, their additional experience in other less technological environments may be valuable.
The major determining factors I see are not age, they are the personality of the person and the environment. The willingness to adopt quickly emerging and rapidly dominating technologies, adapt to the new paradigms they present, and engage in the environments in which they operate are what I see as the determining factors. As far as I can tell, age itself has little, if anything, to do with it. Age only means there is a history which creates an opportunity for a person to stop evolving along the way.
In the meantime, I'll challenge any person half my age to keep up with me. I have twice their experience at adopting, adapting, and evolving my environment plus significant experience at project and management levels.
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