Reading the actual study [1], the headline is a bit deceptive. The study looked at audits between 2000 and 2010, a period during which funding to the IRS increased, and found that generally more funding for audits led to more money recovered from audits (duh). But that $34.3B figure is over 10 years, so it's a tiny fraction of a percent of overall federal revenue, and it's not offset by the amount of more money the IRS would have taken to run those audits.
Also unmentioned is the very real negative externalities that IRS audits cause. Audits disproportionately affect poor people [2], who are also the least able to spend time dealing with them. The United States already has extremely low tax evasion rates [3]. Rather than spending money to catch more of the very few cheaters by audits, other country's tax authorities have found "nudge" letters were found to be similarly effective and vastly cheaper.
Also unmentioned is the very real negative externalities that IRS audits cause. Audits disproportionately affect poor people [2], who are also the least able to spend time dealing with them. The United States already has extremely low tax evasion rates [3]. Rather than spending money to catch more of the very few cheaters by audits, other country's tax authorities have found "nudge" letters were found to be similarly effective and vastly cheaper.
[1] https://www.aaajournals.org/doi/abs/10.2308/accr-52520?utm_s...
[2] https://projects.propublica.org/graphics/eitc-audit
[3] https://www.researchgate.net/figure/Size-and-development-of-...