Could it be because older people are also going to be much more unwilling to try something new ? Noophilia seems to be a feature of youth.
How many young vs old people used myspace or facebook when they first came out? How many young vs old people use instagram, whatsapp, etc ?
Once again, I have no numbers, but I'm guessing it's heavily skewed towards younger people.
I consider myself an early technology adopter, have been all my life. But as I get older I'm less interested, not because I'm older, but because new technology companies are actively choosing to ignore my needs as a customer and my interests.
Soon enough, the major cultural inflection points of leaving elementary, HS, and college will fall behind you. Your job and family take center stage, and your free time shrinks along with the positive reinforcement you get from lightweight social immersion. Then the bloom is off the rose of those latest startups as your net-social focus shifts into more of a spectator mode, posting family photos on Facebook for those now distant friends of yore while caring for your kids, and then caring for your parents. Before you know it, 30 years have passed since you were tuned in and turned on by your last net pet rock.
In many ways, SV startups are truly a young person's game.