I also think it's social reasons, but not really about understanding the internet. More relevant imo is that younger people more often have flexible lifestyles

I also think it's social reasons, but not really about understanding the internet. More relevant imo is that younger people more often have flexible lifestyles where they can take a year or two off from "real life" to eat ramen and live in the office starting a company that's statistically likely to fail. Even if it does fail, it's an interesting learning experience, and they can always get a regular job afterwards. Some older people can also do that, but more are in situations where for family or other reasons they aren't likely to find that appealing.