Because unlike a fee collected at a national park, this funding source is a financial sleight-of-hand. The federal reserve’s income comes mostly from interest on Treasury bills it holds, i.e. federal debt. By law, that income would normally go back to the Treasury, so now apparently some of it instead will go to CFPB. This can only happen because the government is keeping two sets of books (3 if you count the social security system). The CFPB is being funded through accounting fictions. Does it have a budget cap? I don’t know, that would normally be set in the appropriation. since the federal reserve’s “income” is the hundred-billion range, this means CFPB could become one of the largest federal agencies over time, other than Medicare/medicaid and SS.