"That's our number one policy objective -- to change that," Koch said in an exclusive interview with ABC News that aired Sunday.
Where he and Sanders disagree is the solution.
"We've got to get rid of this rather than have more government control, but [Sanders has] at least identified the problem," he said.
Koch said while Republicans have been successful in blocking many big-spending initiatives he believes would be bad for the country, they have mostly ignored pleas from he and his brother to reform the tax system.
"I can see why [Republicans] say, 'Well, there's a tax break over here, we need one here.' Well, that's the wrong attitude. We got to get rid of all of them," Koch said. "It's been disappointing because it's hard to find somebody in politics with the courage to go against what's popular and do what they believe will help people improve their lives."
It's why he says there's no evidence to Democrat's claims that he and his brother act as puppeteers over the GOP.
Koch says it's another reason why he hasn't been able to throw support behind any of the Republican presidential nominees.
"I don't hear any of the Republican candidates talking about this two-tiered system and getting rid of it. So that's why we haven't supported any of 'em," he said. "We haven't put a penny in any of these campaigns, pro or con."
As for the American political system, Koch said he and his brother "would like to get the money out" despite the hundreds of millions his political network Freedom Partners have pumped into Republican campaigns over the past decade.
"The only way to get the money out is get all the goodies that the government's giving to special interests out and that's what we're trying to do," he said. "We now have two-year presidential campaigns, which is all everybody talks about. It's because we have this system of control and dependency, so everybody is dependent, including big companies, on the government to set the rules to give them an advantage."
As for his return on their investment, Koch praised initiatives passed by lawmakers at the state and local levels, but joked that it hasn't all been positive.
"I've gotten a lot of abuse out of it," Koch said.