In theory, anybody can do what these lobbyists do, or rather they aren't doing anything that any person couldn't do - carefully follow everything that goes on i

In theory, anybody can do what these lobbyists do, or rather they aren't doing anything that any person couldn't do - carefully follow everything that goes on in Congress, try to secure meetings with congresspeople and their aides to try and explain their point of view, research things and put favorable facts at peoples' fingertips instead of making them search around themselves, etc. In practice, it makes a huge difference when it's your full-time job to do it, versus individuals acting in their free time. And a bigger difference when you have a big budget to wine and dine people, take them out to nice places, show up at events, do research and organize data for slick presentations, and other such things. And a bigger difference yet when you keep doing it for years and years, building relationships with people, getting experience in who can get things done and is responsive to your input, learning how all of the processes really work, and ultimately hiring more former insiders who already know these things.