It isn't as simply as "the smallest piece of the pie the better," companies pay a lot of money for well-connected people who can get someone to sit down and talk. So while the public could pump tons of money into a GoLobbyForMe site, how you'd measure success Vs theft is tricky.
Plus there's often other corruption less easily combatted, like post public-office jobs, or their spouse/family getting a seat on some board, or similar.
Because I 100% would meet reality where it is and buy my own lobbyist if I could get better outcomes than spitting into the wind at the ballot box
The idea here is that you donate in favor of/against a bill you want. Then representatives that vote favorably to your preference receive a portion of the funds as campaign contributions. If lobbying is so cheap why can't it be done by the people for the people? I see dogs raise more than politicians on GFM.