That's a possibility too. I was thinking it would be more difficult, since he might have run into the whole new rich/old rich thing. He would have been perfectly happy living in a suburban tract home, and that's the type of person he grew up with, so I was thinking that would be the easiest.
Besides, you have fewer choices if your pool of potential friends is rich people.
But they don't all have to be real friends. The interesting thing about Dunbar's number is that it also suggests that people strive to make these 150 relationships even when there are not enough people around (i.e. that's why some people care for celebrities and forge online relationships when real life friends are not enough)
Dunbar's number isn't that simple. It's more like you have an upper limit of 150 person-sized points. You can allocate 50 to one person and only have 100 leftover for more casual acquaintances, for instance.
Dunbar's number refers to group sizes, not friend counts.
From zero to one is a quantum leap - you go from "alone, no one to talk to" to "can talk honestly and frankly with someone". That's the biggest step. Beyond that, of course it enriches your life, but the first friend is the most important.
Besides, you have fewer choices if your pool of potential friends is rich people.