An important factor to note is that it's rare for anyone to sell a first novel written before they turned 30-35; long-format fiction tends to require a bunch of experience of human life that takes time to acquire. So your average mid-career novelist is in their forties to fifties!
Charles StrossWe're currently living with a generation of established novelists who are embarrassingly out of date with respect to social networking, internet skills, and so on.
Charles StrossI was an early adopter: have been on the internet continuously since late 1989, barring a six-month loss of access in the early 90s.
Charles Stross