I feel fairly sure that 'retirement age' quilters in the 1950s/60s/70s were saying the same thing.
Speaking in a general, global sense hobbies go in cycles - sometimes they become all trendy and are flavour of the month, then that dies away as the next 'big thing' bandwagon is jumped on. What could be termed 'domestic arts' such as sewing/quilting, cooking and gardening all seem to be pretty popular in the media (TV etc) and so in life right now, but it'll change to be something else over time probably evolving through various different stages of the original so that we end up with metalwork quilting (art quilts being the precursor?!) or something.
Also as others have said, your life goes in cycles and at some points you just have more time for non-essential time-users (and I'm including kids in the 'essential work' category - not that everybody has to have them, but once you do they kinda need looking after until they are of an age to be a bit more independent). I bet most people have most hobbies when they are pre-late-teen and retired. If you're being pulled at from all angles by essentials like work and children and other responsibilities you need to be pretty dedicated to maintain a hobby like quilting - not saying it can't be done, and I'm sure a lot of you are thinking 'but that is when you most need a hobby' but there are times when it just takes everything to get the essentials done and manage some sleep. Trying to keep a hobby going at those times could actually be more of a stressor than anything else.
I suspect that there are a lot of pre-retirement-age quilters out there - maybe started off by Grandma/Great Aunt/whomever - and they may stop during the years of building family and career, but that doesn't mean that they won't start again when they have time. And then they can infect all of their friends.
