I think the the younger folks are more likely to spot an outsize opportunity where no one was looking at all, whereas an older person might be more aware of an incremental change in an existing business model that presents a new opportunity.
If anything, it was less that they saw opportunity where no one else was looking, and more that they saw opportunity where _everyone_ else was looking and went for it anyway. Everyone else thought the opportunities were so obvious as to have already been solved. Search engines were already solved by Yahoo!, social networking was already solved by MySpace, book-selling was already solved by Borders and Barnes & Noble.
Maybe younger people tend to do things that don't make rational sense from a business perspective, and those are usually the things that become outsize successes in the face of the status quo. Of course, they're also the things that fail way more often than they succeed. That could explain both phenomena, where younger people founded the giant success stories and older people founded more successful things on average.
I hear variations of this refrain a lot. But I wonder, is there any particular evidence to support this, or even a reasonable sounding theory to explain why it is likely to be so?
I have 0 data to back up that armchair analysis.