My understanding of European history is that the Jewish culture was shaped a lot by the Catholic Church.

The Church frowned on Christians taking on business occupations, for business was an occupation of Satan. One had a hard time of getting into heaven when one was in business, which probably increased the size of the indulgences.

But the Church preferred the poor Christians to remain poor, raising large families, working in occupations not really associated with business.

The Jews filled the business void, providing goods and services the Europeans really needed. They became wealthier and could afford to send their children to university. And knowing the next pogrom was not far away, they knew a little wealth helped alleviate the effects of that pogrom. The community closeness also helped.

The Jews of Europe and Americas are a great historical example of a community working together--even though they are/were a minority.