Yes, the western world is primarily more successful due to European colonialism
No, there are many factors on why other regions of the Earth aren't as developed as the west
To a certain extant it widened the gap. The Europeans did have access to richer soil as well, however colonialism, while inefficient, did hurt the nations that were "colonized".
Sykes Picot Agreement, the Century of Humiliation and Congo Free State are a few examples of the negative impact of Euro Colonialism
While developed countries have grown up and thrown imperialism aside, America still immerses itself in it.
To say "failure" is wrong in so many ways, for example China had the opportunity to industrialize just as Great Britain did in the early 1800s but they lacked the easily accessible coal necessary for the process, while Britain did not. Or how kingdoms/tribes in Sub-Saharan Africa were blocked from trade by two major geological barriers, the Sahara Desert and the Congo. And if you notice any pattern in history, trade is by far one of the most important aspects a civilization must have in order to survive. Trade equals science, commerce, and the well being of a society... Europe (Arab World, India, China) had access to such trade which gave them an advantage. Another reason why describing non-European states as "failures" is just arrogant is the fact that Europe had many kingdoms all vying to out compete each other, you see this trend in capitalism so basically who ever competes better survives, and in order to compete better you need to innovate which leads to inventions such as the use of gunpowder for weaponry to the steam engine. Now before the 16th century Europe was on par to many societies across the world, there was nothing going for it till the year 1492 when Columbus kicked off the Age of Discovery, allowing the Spanish to taste the fruit of the New World making other European states want a piece too, this lead to the Colombian exchange allowing Europeans to amass new crops such as potatoes and in general making Europe a lot more populous and a whole lot wealthier. And for many of you, you can see wheres this is going, the Industrial Revolution which began in Great Britain would of never happened if there was no New World providing crops which lead to a population boom leading to an urbanization of many Europeans. And to keep the industrial revolution going, nations such as G.B. turned their forks and knifes to Africa and India. India providing many of the raw material needed for the textile factories in G.B. and British protectorates such as North Nigeria providing rubber, Zambia mining copper, to Accra amassing gold. I am not trying to dismiss the accomplishments the Roman Empire has made or the philosophers of the classical era in Greece, what I am trying to say is that Europe 1492 an onward heavily relied on Imperialism for its rapid growth. And stating other non-European nations as "failing" in some way or fashion is just a wrong interpretation of human society outside of Europe. I mean look at East Asia, 40 years ago it was dirt poor, now it is a major region of trade, prosperity, and wealth. And I am sure most of Africa will follow the same path within the next fifty to sixty years. P.S. to all saying the United States is a modern imperialist nation... that is simply not the case.
Well, the blame is a lot on them. Not completely, though. I mean, define "success". The former culture of these sh*thole countries didn't really call for "success" in the same use of the term success as European's used: they had different values. But, like I say about the black community's crime and poverty problems now, a lot of the blame goes to the rampant racism among whites of the past, because of the White flight, paying them less money, refusing to hire them and forcing them into cramped neighborhoods in the city, but it is also partly their fault and our modern-day fault, because we're, or some other black people, are the ones who commit the actual crime. Just like it will always be partly the fault of the former colonies of the West that they aren't as successful as they can be
Colonialism was over 200 years ago, if people can't get stuff straightened out and learn how to advance things and blame their failures on some 200 year old stuff, then they're just retarded.