I can imagine a time in my distant future where I will feel unappreciated and/or unable to keep up with technology the way I can today (though admittedly even today it's not an easy task given the trajectory. I'm pretty certain we're on an exponential curve).

What is the gift that will keep on giving? Write about what you know. Write about your experiences and insights. Even thousands of years from now people may come across your work and given the advances they will be living amongst will almost certainly be interested in what you had to say.