IRS audits of high earners are incredibly effective at raising tax revenue and reducing deficits.

New research shows that for each $1 spent on an audit of a high income individuals, the audit recovers $2 in tax revenue immediately, and then another $10 over the next 14 years as audited individuals voluntarily pay more in taxes due to deterrence effects

https://policyimpacts.org/research/67/a-welfare-analysis-of-tax-audits-across-the-income-distribution