Why do a significant part of the countries of East and Africa fall into colonial dependence on the countries of the West?

Why do a significant part of the countries of East and Africa fall into colonial dependence on the countries of the West? Could the history of these countries have developed differently?

The countries of East and Africa became colonies of European powers, because at a certain stage of development, they were very far behind in technical, economic, social, political and all other aspects. The history of these countries could hardly have developed differently, because the main reason for the development of Europe is competition. After the collapse of Rome, many strong powers were formed here, which were forced to constantly develop in order to survive in the struggle with each other, and all the eastern and African strong powers (Ancient Egypt, Mesopotamia, the Arab Caliphate, India, China) developed in isolation, so at such a pace growth was not observed in them.