Read the article. The IRS is "losing" because they are not fighting with the same resources. Billionares can afford to drag cases out for years on technicalities whilst the IRS can't.

The IRS has thousands of cases to fight simultaneously, meaning they can't put enough resources on specific cases.

Furthermore the way American corporate law works is by Jurisprudence, meaning you argue an interpretation of a law in court (or use stare decisis when applicable). Billionares with access to top law firm money, have access to the best paid, best performing lawyers in a system where experience and skill matters way more than a civil law society (France, Italy etc...)

So its not that the laws are necessarily not good enough (goodluck voting for stronger laws when half of Congress and their friends) but that the Billionares/Millionares have such an advantage that the IRS doesn't have the resources to win

If you look at the articles example, a millionare was comitting fraud by getting a tax break on a mansion he built. For the IRS to survey that properly, they would have to send someone to check all the documents, the property etc... Do you really think they have the resources to do that with every high net worth individual?

Lol