I think blue and yellow dots don’t tell the whole story. To answer your main question, yes I think people segregate themselves with the group they identify with. Not all
People do it, I’m talking in general terms. I think social-economic class has a significant impact on this. I also think how diverse an area is is makes a significant impact. In the exercise of the blue and yellow dots there are only two choices. What if there were 7 colors? Every color of the rainbow. Then other factors come into play for who you would identify with. Also, what if the yellow dots make more money than the blue dots? And, you’re a yellow dot making the money a blue dot makes. The blue dots live near better schools, less crime, more green space, are you as a yellow sit going to move out of your perceived group into your new socio-economic group? Probably. Will the blue dots care? Not at first. Not until it seems like a lot of yellow dots are moving in. If the property value holds up, crime stays low, and people seem to have similar values, the blue dots might continue to stay. If not, they move.
Back to the 7 colors of the rainbow. Once you are one of the many and all neighborhoods and workplaces within a certain distance are very diverse things change in my opinion. Your area is just diverse period.
Also, mentioning workplace. I know someone who says in America certain jobs are now very occupied by immigrants, and especially if they speak another language, but that doesn’t have to be the case, the people who used to do the job no longer feel comfortable doing it. People in America say we need Hispanic immigrants to work our fields, because “Americans” won’t do it. Yet we have Americans who need jobs. Is that really true? Or, is there a segregation dynamic going on? Someone I know who owns a few McDonald’s once said to me that 40 years ago he employed teenage kids from his neighborhood and now they won’t take those jobs. Basically, he was saying the middle class white kids won’t do it anymore so his pool of labor is lower class now. It wouldn’t surprise me if he also meant not “white.”
I think this happens a lot less among professional jobs that earn high incomes and high income neighborhoods also.
Also, it’s worth mentioning that sometimes groups get sort of pushed out. New immigrants, or new groups, make a move into a neighborhood or industry and their families, friends, peers follow suit.