If the lobbying they do is unfair, then they should change the rules around lobbying
Who is "they"? Plenty of people do want to reduce the amount of money in US politics, but they come up against the same money that's behind the lobbying in the first place.
1. https://s3.amazonaws.com/s3.documentcloud.org/documents/2091... see q32
The legislators who have the ability to change the rules around lobbying are at the receiving end of millions of lobbying dollars, and they don't want the money firehose to stop.
SCOTUS stopped them in their tracks.
A constitutional amendment is absurdly politically expensive.