There are many examples of economies where wealth inequality is not "ever widening." Even in very recent US history there have been times of decreasing inequality, such as in the wake of the Great Recession.
Sustained decreasing trends have been observed in many Western economies in the period from the late 19th Century to the 1980s, when many of these economies introduced redistributive measures.
Corporations are the dominant form of all social constructs currently regardless of governments or cultures.
Markets and inequality also long predate corporations, which emerged in the early modern period.