But campaigns DON'T get that pot of money. That's the point. That money stays independent, and is spent independently, even though it's spent to help or hurt a candidate, or a ballot measure, or an issue in general.

The money the campaigns get is already subject to pretty tight individual campaign contribution limits.  I suppose they could lower those limits even further, but what does that really accomplish?  That just takes the little guy out of the equation. The big guys now give their money to independent SuperPACs which is legal as long as they're not actual campaigns.  

Other than perhaps tightening the rules on non-coordination with campaigns (which surely takes place behind the scenes), there's really no putting the genie back in the bottle for independent spending. As government has grown bigger and more powerful, there's more incentive to influence it. The only way to reverse that is to shrink the size and scope of government (i.e. reduce the incentive to control it).