I think people adjust their topics of conversational small talk according to the focus of their life at that time. All ages groups do it. A lot of younger parents like talking about their babies' and toddlers' development to others they bump into. Teenagers talk about bands or singers they like or gaming or whatever or 16-18 options. People of working age whose children have grown up tend to talk about work hassles with management, issues with elderly parents, their children's uni lives, etc.
So for elderly people, unless they are still doing a part time job or volunteering or going to the WI or on the parish council or go travelling regularly i.e. somewhere there is a specific focus, what conversation are they going to be experiencing day to day? It's probably just the small talk and chit chat of others they bump into or go for a coffee with. And the first question they'd probably ask that neighbour they bump into putting the bins out, and their mate Norma they saw at lunch on Tuesday, or the man who owns the cornershop when they went in for a loaf of bread is "how are you, how have you been?" And of course the very first thing most people would respond with is LITERALLY how they've been.
If all the people they bump into or go for lunch with are a similar age to them then it stands to reason their response to "how have you been?" might not actually be "fine, thanks, great" like most younger people might say, but more "well, I've had a terrible chest infection actually, and Dave was in hospital the week before last with something similar. But we're lucky, at least we're getting over it - did you hear about poor Carol who used to work in the florist? She dropped dead suddenly at home last week.!"
Their life basically becomes a list of who they bumped into/met up with and how well they are (or not) at the moment. So that's often the only "news" they have to tell their families when they see them. I think you probably have to make a concerted effort when you're older to make your topics of conversation with family more varied eg politics, developments in your local area, books you've been reading or newspaper articles you read that day, a holiday or trip you took somewhere new, something to do with your hobby that you learned, a concert you saw, a new restaurant or recipe you tried. If you don't actually DO many varied things from day to day then yes, your life is going to be very "small".
I have a feeling I'm going to be in the "small life" elderly group when I'm older, I'm quite happy just pottering about when I'm off work (apart from travelling and I'm sure when I'm a lot older my health won't allow me to do that forever). I'll be boring my boys senseless when they're older, even more than I do in middle age now !