Unchecked, power consolidates. Marx notes in Das Kapital the Capitalist will always seek to capture regulatory bodies in the name of profit.

The goal, thus, becomes to distribute political power (including wealth) as diffusely and evenly as possible, and create a system that checks efforts from outside to attack and break its integrity.

The USSR was beleaguered from the beginning by sanctions by the rest of the western world, as pressured by President Wilson. As problematic as the Leninist model was, we don't know how it would have fared if it were left to engage with the world on its own terms.