Because people seem to associate fun with spending money!
Until fairly recent years, the average family had fun staying indoors. Playing board games, cards, watching films and documentaries together, drawing, painting, reading. Going for nature walks, browsing the shops. Reading a magazine in the garden. All pitching in with household chores and gardening. Occasional days out to a museum or a longer walk with lunch in a pub. A drive to a local beauty spot. Enjoying each others company (or bickering at times, but there wasn't the isolation many seem to want from their kids now). On day trips to see relatives, we often stopped at a Little Chef for a cheap meal.
Nowadays, many families seem to assume fun involves splashing out. Entrance fees, cinema and theatre tickets, exciting day trips, browsing shops must include 'treating' themselves to a few things, and regular sit downs in coffee shops, restaurant for lunch. Even with kids, it has to be somewhere like Nandos or Giraffee or Waga Waga.
Nature walks are 'boring' so it's a children's treasure trail at an overpriced farm. Lunch in farm shop as parents too busy to pack a picnic. Kids want days out at Legoland or ChillFactor.
Perhaps there's a growing need for more 'stimulating' fun. Kids get used to expecting souvenirs in gift shops, having lunch in their favourite restaurant afterwards. Cinema is nolonger special occasions only, it's a popular weekend outing. I also think too many kids are put into afterschool dance, music, activity clubs. Parents often work all week, so weekends are catching up on all the admin and housework, AL packed full of exciting fun trips. Lots of families don't even manage eating around a table together each day. Parents have their own TV so they don't have to take turns with kids.
Like a chronic overstimulated state, with everyone seeking the next dopamine buzz. Very sad.
Not all families clearly. Mine like quietly chatting in lounge, reading, talking, kids playing.