The way I think about it is this. Governments and companies are both organizations made up of people. Governments have additional powers (for instance, military force, police power, etc.) over companies. The checks and balances for gov't abuse of power depend on the type i.e. representative democracy, republic, etc. And the checks and balances for company abuse of power are however the markets are configured.
There are different incentives at an organizational and people level both in gov't and companies. But in general, I tend to think its easier to prevent "company abuse" of power b/c ultimately they have to deliver a product which people can choose to buy or not - in this sense we all have a direct democracy with companies, unlike Gov't.
For instance, if I choose to not buy any more Google products, then however small and insignificant it may be Google is going to notice my change of preference on the bottom line of financial statements just as will the other company whom I deem better aligned to my preferences.
This type of direct control is currently not possible with governmental institutions unfortunately.