The 1920s were a period of economic growth and transition. Real wages for most workers increased, while stock prices advanced as much during the 1920s as they had in the previous three decades
The imperialists needed workers to work on the land that was colonized. The locals were not an option because they were often either insubordinate, or they were protected by the law. That's why having slaves to work in those colonies was great, which is why they got them from Africa.
