+1. A WhatsApp group with 10-20 ppl (in similar stages of life) worked well for a while for organizing hiking/tennis/squash/some sport/DotA. We got consistently 4-5 people including their spouses showing up. Usually 2-4 weekends a month. With that size, many people can comfortably pass on the invite.
Then organically these tend to turn into trips together or simple hangouts for someone's birthday or a holiday.
Buffet surely made lots of upgrades and has added plenty of material comforts.
But it is quite possible to be a kind of lazy where even 10-20x current wealth, people would live where they currently live. American neighborhoods are reasonable that way. It is just primary home and they would holiday/vacation wherever.
It is highly unusual for someone to stay put after their net worth increases tenfold. Normally, you would expect an individual to seek out more elite social circles and embrace a significantly more opulent lifestyle. Not having that isn’t a sign of laziness (one can be certain that someone like Warren Buffett lives exactly as he chooses) but rather a reflection of the rare ability to decide that what he has is already enough.
Then organically these tend to turn into trips together or simple hangouts for someone's birthday or a holiday.