Political interference: European powers often intervened in the internal affairs of their former colonies, supporting certain factions and suppressing others. This prevented the colonies from developing stable and democratic governments and created conditions for civil wars and other conflicts. For example, Britain supported the monarchy in Egypt and suppressed the nationalist movement led by Saad Zaghloul.
Military occupation: In some cases, European powers resorted to military occupation to maintain their control over their former colonies. This was especially true in Africa, where European powers competed for control over territory and resources. For example, France occupied Algeria for over a century and brutally suppressed the Algerian independence movement.
Cultural assimilation: European powers often tried to assimilate the cultures of their former colonies into their own, suppressing local languages, customs, and traditions. This caused resentment among the colonized peoples and hindered the development of their own national identities. For example, the British tried to impose English language and culture on India, which led to a backlash from Indian nationalists.
These are just some of the ways that European countries prevented success in the years after independence. The legacy of colonialism continues to affect the development of many countries around the world today.