Yes, agencies have all these capabilities, but at the same time they rarely sway the practical course of history. When the "euromaidan" demos in Ukraine forced regime change, and the Russians hacked and leaked all US/EU diplomatic chatter around it, the contents were utterly banal and predictable. There was no grand conspiracy or execution, just a bunch of interests scrambling to react.
Intercepting communications gives them a leg up, but that's about it.
People love to assume that the CIA/NSA/etc are all powerful all knowing cabals running the entire world, while also believing that government is inherently incompetent.
Anybody who’s been in a large organization, even one that’s highly selective or difficult to join, knows that they’re as a rule chaotic, dysfunctional, and reactive with no coherent or coordinated planning. They’re also composed of individuals who usually run the gamut of moral and honest to deceitful and self serving - but the “sociopathic puppet master genius” is more of a fictional archetype than something that exists in reality.
This would be my take too. From all the past leaks of cables, the perhaps most hilarious revelation is the overall humdrum, including the speculative, often incorrect, and sometimes rude chatter between diplomats and intel people.
Intercepting communications gives them a leg up, but that's about it.