Why do you have to be 20 to be doing something interesting? Also why is it assumed that every new innovation that some 20 year old ivy league drop comes up with

Why do you have to be 20 to be doing something interesting? Also why is it assumed that every new innovation that some 20 year old ivy league drop comes up with is good for our society and our culture? To me most start ups are just superfluous, these apps and such are created just to make our lives slightly more convenient in most cases, they rarely improve the human condition or outlook. Go ahead and glorify the startup culture but I have more respect for the grizzled old devs that have created the foundation we stand on today and the people moving things forward incrementally.