My claim is, that the market is encouraging segregation less than society. Jobs force people to work together. If nobody forces them, they often just don't work together, and stay in their bubble.

It's kind of a six-of-one half-a-dozen-of-the-other situation IMO. Modern society does tend to have extreme social bubbles, but those are also a product of market forces, which in turn were influenced by previous states of society, etc etc back to the beginning of time.