It's funny how you've framed the question so it is

--megacorporations vs totalitarian governments--

as if one automatically had to exclude the other. Or as if you had to choose one or the other. It's as if you are congenitally incapable of visualizing how any capitalist institution of any kind could possibly lead to evil of any sort. Maybe we can have both: totalitarian governments AND evil corporations..

Megacorporations have never ruled the world because they didn't exist in the past, they weren't possible due to the limited communications and transport of the time and the boundaries nations put on each other's trade. They are possible today, in fact, they are growing by leaps and bounds, in power and number. And the legal and financial structures to facilitate them are being put in place, lke NAFTA, WTO and World Bank and other international trade agreements, international financing, etc.

Don't worry. Just because a global megacorp MIGHT possibly be a bad thing doesn't mean all capitalism must be evil. I didn't mean to threaten your moral universe. And my speculating about a possible science fiction future is not an attack on your world view or your ideology. You get so touchy when you think somebody is bad-mouthing business. It as if you were afraid someone might stumble onto something...

However, we do know that even as early as the 17th and 18th centuries
large companies like Hudson's Bay and East India could already provoke trade wars between great political powers, and they've been getting better at it over the years. Countries go to war primarily for economic reasons, even committed capitalist nations. It's only a matter of time before they figure out how to dispense with nation-states altogether as a substrate on which to carry out their plans and get rid of the idea of "country" altogether. In fact, with the enmity existing between business and government expressed by conservatives, it's a wonder this hasn't happened already.

As you frequently point out, the corporation is a much more effective means of organizing capital and labor than the nation-state, and it is self-funding to boot, not requiring coercive taxation to support itself. Now that multinationals sprawl across continental boundaries and oceans, and lobby governments into passing legislation favorable to international operation and foreign trade, they will soon show that they are better able to take care of their worker/citizens than nation-states are, providing health care, security, financial services, all the "benefits" of political units.

What do yo think the founding fathers would have thought of that?