Among the many things God hates are haughty eyes, lying tongues, hands that shed innocent blood, and hipsters. More or less out of spite, God bestowed special favor on the newish people, so hipsters couldn't pretend to have liked them before they were cool. It's worth noting that variant readings of Leviticus specifically prohibit skinny jeans and ironic glasses. In fact, modern research has determined the verse banning men from cutting the sides of their beard was really a law against man-buns.
Rather than choosing an oldish people, God specifically called Abraham to establish a fresh, different people group (Genesis 12:5). The oldish people were more connected to the time of Noah. In order to really set His people apart, they had to be newish. This is also echoed in the New Testament, as Peter notes that "once [believers] were not a people, but now you are God's [newish] people" (1 Peter 2:10).
God did not choose the newish people because they are inherently better than oldish people. Ten seconds talking to a millennial proves that. Rather, the point was to demonstrate His mercy, sovereignty, and His plan to bring about the birth of the Messiah who happens to be a
one of the Jewish people.