while some colonistaion may have been besign - the reality is it included slavemaking, guns and ships canons, genocide in various mixes; and across most of Asia where 60% of people lived and Africa colonisation meant extracting a colony's resoutces mainly for the benefit of the empure and its trade; the top down admisnstrative systems of colonisers mainly controlled peoples; take the indias subconstunet for example; this placed a quarter of the human race under the adminstration of British Raj - alumni of Mahatma Ganddhi calculated that ar best the epopel of India were paying compound tax of 80%- ie only 20% of their labors and country's assets benefited them.
Even if we can dbeate some numbers it was clear at the birth of teh UN that a huge number of nations needed freedom; but taking the British case as the biggest example- world war 2 had ended the uk's budgetaey surplus; the nation would rely on eg usa to be kickstarted; so while it hasrily handed out freeod=doms eg to placesd that had been British Raj- it offered evry little immediate comoendation and it passed on the same top-down system that had centuries of of povery classed embedded in it.
So it shouldn't be surprising taht miracles were needed to free peoples to rise and rise. This is a fascinating subject to map all over the world from 1945. There may be a few sity port cases (compact populations less than 1 like siganpore where great leasderhip set the natins peoples on the best expoential rising f all