A huge proportion of the world was still under direct colonial control after WWII. Like most of Africa, swathes of Asia. Pick a country on a map and look at the date it was granted independence. I can almost guarantee that it will be later than you expected. Post-WWII is not a low point for colonialism.

I would further argue that many of the countries that were granted independence only received the ability to install administrators who were of an indigenous ethnic group. Trade agreements and terms dictated by loans from groups like the international monetary fund still directed a large proportion of domestic and foreign policy. So even though the government of a country may have had a constitution and veneer of democracy it was still operating at the behest of foreign interests (ex. Shell in Nigeria, Firestone in Liberia, Exxonmobil in Indonesia, etc.), who propped up puppet leaders that allowed them to continue to extract resources under the same or similar agreements they enjoyed under colonialism.