Government Capture is a term used to refer to the shift of governments from representation of the interests of the People to representation of the interests of the few. Representative Governments are subject to capture because all representative governments are expected to be subject to influence by their constituents. Government Capture is really a result of the tendency of those who have the largest stake to devote more effort to influencing their representatives.
Perhaps one of the mechanisms which leads to government capture is the perception that various interest groups represent the wishes of various segments of society. These various interest groups, of course are also subject to capture, so it can also get very confusing. Groups claiming to represent small business may be representing the interests of large business. Groups claiming to represent the Environment may be representing a particular point of view, etc.
Government Capture is constantly being attempted, and probably occurs slowly. An example would be the evolution of Corporations in the US. Corporations excesses were one of the things that prompted the American Revolution, and early on, American Corporations were individually chartered by State Governments to meet specific public needs and were very limited and very regulated. Corporations evolved very slowly, from limited entities which served the public to what they are today. That evolution involved many favorable court decisions which are evidence of Judicial Capture, laws enacted which favor particular Corporations or economic sectors which are evidence of Legislative Capture, and appointment of people favorable to corporate interests in Administrative Agencies which is evidence of Regulatory Capture.