https://www.propublica.org/article/irs-sorry-but-its-just-easier-and-cheaper-to-audit-the-poor
«For now, the IRS says, while it agrees auditing more wealthy taxpayers would be a good idea, without adequate funding there’s nothing it can do. “Congress must fund and the IRS must hire and train appropriate numbers of [auditors] to have appropriately balanced coverage across all income levels,” the report said.
Since 2011, Republicans in Congress have driven cuts to the IRS enforcement budget; it’s more than a quarter lower than its 2010 level, adjusting for inflation.»