Why Shakyamuni Buddha choose Indian subcontinent as a favorable place to teach Buddhist way of living?

Current India was previously not as big and united as it is now. Multiple countries quarrel for existence. Life was not normal for people. Chaos and Imbalance was on its height. Is that the reason, Shakyamuni Buddha choose Indian Subcontinent as a favorable place to teach Buddhist way of living? If so, next destination for Buddha to teach may be Syria, Iraq, Afghanistan or even United States. If next Buddha is seen in some other place besides Indian Subcontinent, will he/she be recognized as Buddha? What if Jesus was a form of Buddha? What if new Buddha change the way Buddhism is what we are following, according to current situation?