Costly elections interest groups provide much of the money. Weak political parties create a vacuum strong parties could finance and protect officeholders. A message that is compatible with American values. No group gets it way all the time. Very powerful groups fail to accomplish all their goals.
Major groups oppose one another, including business groups.
Those who know how to play the game and do it well do better over time. Federal and state budgets are loaded with laws and subsidies that benefit and support groups who know how to play the game. Help people who help you. Direct Lobbying personal contacts, testifying, legal advocacy.