Any government which derives it's control over people without the individual consent of those persons, doesn't need to "become dictatorial", it already IS dictatorial, by virtue of the involuntary aspect / lack of consent in the relationship.
To the unconsenting individual whether the dictatorship is by one person, by several, dozens, hundreds or thousands, the means used (an involuntary relationship backed by threats of force or actual force) is what makes it dictatorial.
Governments and corporations are brethren, in that they exist to give some people "extra rights" and legal immunity which other people don't have. Both should be abolished since they are antithetical to equal human rights.