Well, without colonialism many European countries would still be poor. The Spanish gold would have never reached Europe.

There would have still been some money that spurred the early enlightenment from the Dutch East India company, and the Silk Road, but none or few of the economic developments in Spain, France, Belgium or England would have been possible in the first place.

Eastern Europe would likely be better off, as colonialism from the Middle East by the Ottomans never would have happened.

On the same token today, if say... Congo had not had its wealth stolen, that country would have a lot of gold.

Basically, if it were not colonialism, many European countries, and the Ottoman Empire, would be significantly poorer; assuming trade and diplomatic relations had replaced colonialism, Africa, China, and India would be a lot richer trading their resources instead of having them taken through battleship diplomacy and force.

It is hard to say what Australia and North America would be like. Colonialism obviously does not create wealth on its own, as many Imperialists will argue; if that were true than South America should be as well-off as North America. I doubt North America and Australia would have had their economic developments however, without the presence and intervention of European powers.

I do not think the genocide and ethnic warfare between Europeans and Native Americans and Aborigines was necessary, but illegally and forcibly stealing land to create the settlements and port cities which would become necessary for those continents' economic developments probably was.

Colonialism is relevant to economic conditions today, because the economic conditions in the first place would not have existed the same as they are today without colonialism. Both the good conditions of Europe, and the bad/developing conditions of places like India, would not exist.