The thread you link to is filled with errors and random clichés about Versailles and the rise of fascism. All involved would do well to read more before forming their opinions.

The suggestion that the loss of African colonies mattered much to Germany's economic problems is hard to substantiate; the data on German imperial trade suggests that they were of little economic importance.

Contemporary British analysts -- imperialists-- thought the German colonies in Africa fairly worthless. They held out the possibility that there might be resources that _could_ be developed in the future, but there's no suggestion that its of significance at the time.

A useful table summarizes the scant economic importance. As of 1910, neither Germany's exports to nor imports from its colonies amounted to %1 of these categories. For a few particular commodities, notably rubber, colonies amounted to a bit more, but it's hard to make a case that these colonies mattered other than ideologically.

There is an interesting line of scholarship on the ideological implications of Empire, but there's no real economic importance to Germany. One can see the drive for the prestige of an empire as envy of Britain, a sentiment famously expressed by Bernhard von Bulow in 1897, and this sentiment was most forcefully implemented not in Africa, but in Asia

The days when Germans granted one neighbor the earth, the other the sea, and reserved for themselves the sky, where pure doctrine reigns – those days are over.

{snip}

In short, we do not want to put anyone in our shadow, but we also demand our place in the sun.

That line "our place in the sun" is a shorthand for Germany's imperial project -- not so much a pursuit of practically valuable objectives, but a sense that Germany has been done out of something, is owed a more equal footing with Britain. This "weltpolitik" has great importance for the origins of the First World War, but very little economic importance to Germany, either before or after.

See:

Crabtree, W. A. “Economic Resources of German Colonies in Africa.” Journal of the Royal African Society, vol. 16, no. 62, 1917, pp. 125–134.

Henderson, W. O. “Germany's Trade with Her Colonies, 1884-1914.” The Economic History Review, vol. 9, no. 1, 1938, pp. 1–16.

Smith, Woodruff D. “The Ideology of German Colonialism, 1840-1906.” The Journal of Modern History, vol. 46, no. 4, 1974, pp. 641–662.

Mambo, Robert M. “MITTLEAFRIKA: THE GERMAN DREAM OF AN EMPIRE ACROSS AFRICA IN THE LATE 19TH AND EARLY 20TH CENTURIES: AN OVERVIEW.” Transafrican Journal of History, vol. 20, 1991, pp. 161–180.

Kaiser, David E. “Germany and the Origins of the First World War.” The Journal of Modern History, vol. 55, no. 3, 1983, pp. 442–474.