"The rot set in back in the 19th century, when the US legal system began recognizing corporations as de facto people. Fast forward past the collapse of the ancien regime, and into modern second-wave colonialism: once the USA grabbed the mantle of global hegemon from the bankrupt British empire in 1945, they naturally exported their corporate model worldwide, as US diplomatic (and military) muscle was used to promote access to markets on behalf of US corporations.
Corporations do not share our priorities. They are hive organisms constructed out of teeming workers who join or leave the collective: those who participate within it subordinate their goals to that of the collective, which pursues the three corporate objectives of growth, profitability, and pain avoidance. (The sources of pain a corporate organism seeks to avoid are lawsuits, prosecution, and a drop in shareholder value.)
Corporations have a mean life expectancy of around 30 years, but are potentially immortal; they live only in the present, having little regard for past or (thanks to short term accounting regulations) the deep future: and they generally exhibit a sociopathic lack of empathy.
Collectively, corporate groups lobby international trade treaty negotiations for operating conditions more conducive to pursuing their three goals. They bully individual lawmakers through overt channels (with the ever-present threat of unfavourable news coverage) and covert channels (political campaign donations). The general agreements on tariffs and trade, and subsequent treaties defining new propertarian realms, once implemented in law, define the macroeconomic climate: national level politicians thus no longer control their domestic economies.
Corporations, not being human, lack patriotic loyalty; with a free trade regime in place they are free to move wherever taxes and wages are low and profits are high. We have seen this recently in Ireland where, despite a brutal austerity budget, corporation tax is not to be raised lest multinationals desert for warmer climes.
For a while the Communist system held this at bay by offering a rival paradigm, however faulty, for how we might live: but with the collapse of the USSR in 1991 — and the adoption of state corporatism by China as an engine for development — large scale opposition to the corporate system withered.
We are now living in a global state that has been structured for the benefit of non-human entities with non-human goals. They have enormous media reach, which they use to distract attention from threats to their own survival. They also have an enormous ability to support litigation against public participation, except in the very limited circumstances where such action is forbidden. Individual atomized humans are thus either co-opted by these entities (you can live very nicely as a CEO or a politician, as long as you don't bite the feeding hand) or steamrollered if they try to resist."