Why would a goverment not be legitimate

Political legitimacy is considered a basic condition for governing, without which a government will suffer legislative deadlock(s) and collapse. In political systems where this is not the case, unpopular régimes survive because they are considered legitimate by a small, influential élite.

Explanation:

less available tax revenue

this basically means that when they get money from taxes wirth having a lower gdp they get less then what others have with a higher gdp