[berberous]

The US does go after the wealth for tax fraud. I think the bigger issue is that the wealth pre-emptively hire CPAs/lawyers to take maximum advantage of tax rules in a way that may not be prohibited, innovating faster than legislators can act.

[actually_a_dog]

IRS Audits Few Millionaires But Targeted Many Low-Income Families in FY 2022: https://trac.syr.edu/reports/706/

[berberous]

The IRS may be underfunded, but it's misleading to say the IRS does not go after the wealthy for tax fraud. The chart in that article shows $1M+ earners to have the highest audit rate, albeit some of it correspondence audit, and says 25% of audit man hours are spent on millionaires.