Very true. Government regulators routinely fail in their jobs, either through direct criminal complicity with the violators or by gross negligence. Then, when their failures are revealed, they ALWAYS claim that they need more laws, more people and bigger budgets. Nobody in the regulatory agencies is ever investigated, prosecuted or otherwise held accountable no matter how badly they perform.
The 2008 financial crisis is the absolute perfect example. The government has the SEC, OTS, OCC, CFTC, FDIC, FBI, etc. all with regulatory power in the financial industry. Yet this army of bureaucrats utterly and completely failed to carry out their most basic responsibilities AND neglected to enforce the laws even when the criminal practices of the big financial firms was openly exposed. Government solution? More regulations and more bureaucrats in a new CFPB.
EPA agents must have been too busy (or too incompetent) to actually test a few vehicles for compliance with emissions laws. They were probably off threatening and harassing some small business owners who can't afford full time lawyers and compliance officers.