This is a subtle and difficult thing, but I promise you it is true: the IRS is not primarily scored on revenue generation. Their incentives are (approximately)

This is a subtle and difficult thing, but I promise you it is true: the IRS is not primarily scored on revenue generation. Their incentives are (approximately) hire more IRSians, minimize complaints to Congress regarding the tax code, minimize complaints to Congress regarding the IRS specifically, efficiently administer taxes, and generate revenue, in order. There are a lot of changes that are within the IRS' authority to make which would be net-positive from a tax collection perspective and which it would not do and, if it did, would be undone from above. One is "radically increase the number of audits administered."