Transportation was a large issue: I unfortunately don't have a citation, but my notes from a class I took a couple years ago are as follows:
There were 2 ages of Imperialism: Pre-industrial and industrial, the 2nd age beginning in the late 19th century.
Important differences in overseas expansion efforts between the pre-industrial and the industrial eras
- Material goods
- In the pre-industrial era, European countries expanded overseas to seek precious metals, manufactured goods such as cotton and silk textiles, and luxury items such as spices (1st era)
- In the industrial era, imperialism occurred to secure supplies of raw materials for European industrial enterprises and to secure markets for manufactured goods (2nd era)
- Geographic Spread
- In the pre-industrial era, limited technological capabilities generally forced Europeans to colonize very limited areas such as islands and coastal enclaves—only in North America could extensive areas be settled
- In the industrial era, technical advancements and mechanical superiority allowed European, American and Japanese forces to physically conquer vast swathes of foreign territory
One reason could be that the late 19th century just isn't that long before WWI, and the beginning of the end of direct Imperialism. That isn't much time to set up colonies.On the other hand Britain managed to heavily colonize North America and Australia before this time, and likewise, Spain did South America.
If you look at Africa as well, there were instances of direct colonization, most notably the Boers of Orange Free State and Transvaal whom were of Dutch descent, and the colonization of South Africa.