That's what growing old looks like, friend. The world we knew is going away, to be replaced by a new world for new people who care about different things.
I'm sure people who genuinely loved tending to mules and horses "lost interest" when regular folks started using trains and cars to travel. It's just how it is - humanity goes forth, as it will.
But that is only partially true. People socialize a lot less than they used to, things changed in a fundamental way. If you look around in NYC 50% of storefronts are empty and unoccupied. There are multiple reasons for the latter but it still is a fundamental change. Maybe the virtual world is thriving in some hot pockets but the analog world is becoming less welcoming to many of us.
You live in a small rural community. Industrial revolution happens, and slowly most people move to cities. If you stay in the little town, you feel lonely, "people don't visit anymore". If you move to the city and try to live by the old rules of rural community, you'll be upset: "people on the street don't say hello and good morning anymore, they don't socialize!". But they do - just by different rules, across different groups from before.
We are going through an industrial change on a level last seen 100 years ago at best (electricity, cars, factories). Life is changing accordingly.
I don't know if people socialize less, but they socialize differently. I see plenty of people riding buses, trains, or walking around and endlessly messaging someone on their phones. It's easy to find complaints mocking these people as being drones and slaves to their phones, but they're actively socializing everywhere they go. They're just doing it with someone you can't see.
Most people 30 years ago weren't chatting up everyone on the bus during their daily commute. They were merely tolerating people. People today are silently talking the whole ride these days.
Yeah, it's harder to sit down and have dinner with friends and family every week than it used to be, but it's easier than ever to talk to them all day if you want to.
I know my grandparents would have people over for dinner almost daily, but they never left their small town. They knew those people their whole life and never lived more than 20 minutes away. Seeing them was easy, but if those people couldn't visit for dinner, that was it. There was no talking to anyone else for days if nobody randomly dropped by. Now people often move hundreds or thousands of miles from home, yet it's possible to have a conversation all hours of the day if you want to.
It used to take about three generations before everything you love fades from public memory. Now it's less than one.
Soon Warhol's adage will be proven right: 15 minutes will be the lifespan of not just fame, but of all shared memory.
Soon thereafter, all individual memories will last just 15 minutes. Then long term memory will no longer exist.
It's also reasonable to point out that this is perhaps a trap lots of people growing old fall into, and also perhaps not the most healthy thing to do.
It might be better to adapt rather than pine, if that's possible.
I could pine for the days of my favorite rock bands not being considered 'classic rock'. I could also try and enjoy new music that isn't strictly 'classic rock'.
It relies on more assumptions than just that. It relies on the assumption that naturalism and materialism are true, and hence an afterlife is very unlikely (if not impossible).
You can reject naturalism and materialism without agreeing that God exists. Consider the late 19th / early 20th century British idealist philosopher John McTaggart Ellis McTaggart (who at Cambridge acted as the mentor of Bertrand Russell and G. E. Moore) – McTaggart insisted that God did not exist, that he knew God did not exist, that God's existence was impossible – but he also claimed that time and matter are illusions, and the true reality is timeless immortal souls and their eternal love for one another.
Conversely, it is possible to believe in God without an afterlife. The ancient Greek philosopher Epicurus denied an afterlife, but he did not deny the Gods of ancient Greek polytheism. (Probably, if he had lived in a more monotheistic culture, he would have dropped the plural.)
The ancient Jewish Sadducees, who controlled the office of High Priest up until the destruction of the Second Temple in 70 CE, they rejected the Pharisees' belief in resurrection of the dead. (The Pharisees are the historical progenitors of contemporary Judaism; and, while Christianity conflicted with the Pharisees a lot, witness how much they are criticised in the Gospels, one can't deny that Christianity took a lot from them, including the belief in a future resurrection of the dead). It isn't entirely clear what exactly the Sadducees believed about the afterlife, but certainly by some accounts they believed that death was extinction. (Part of it depends on whether they understood "Sheol", the grave, to simply be a symbol for extinction, or an actual place where the dead are conscious.)
I'm starting to lose interest in the world.