Question

What factors help to explain why the United States and the Soviet Union became rivals instead of allies?

Answer 1

Competing military, economics, different politics, imperialism and geopolitics.

Explanation:

The USSR and US competed on a multitude of levels, but primarily these because:
Military - Literally every major world power wants to have a gigantic military, and during the "Cold War" Era, these two powers were at the top.
Economics - Competing businesses and corporations, infrastructural investment and trade, also competing currency values.
Politics - Obviously the Communist/Marxist/Socialist ideal vs. Capitalism/Free Market.
Imperialism and Geopolitics - Both nations wanted to control as much land and influence the most on a global scale, specifically both nations wanted the Middle East.