And the rich have those in plenty. They find every little thing they can and push it as far as they can without getting caught. Sad reality is the IRS has been more focused on the little guy since at least Obama.
The IRS is focused on the "little guy" simply because that is where the money is. The little guys make an outsize number of easy-to-catch mistakes, and don't have the wherewithal to fight, so the IRS "ROI" on auditing the "little guy" is much higher than auditing a lot of the bigger guys. However, most bigger guys do undergo audits on a more regular basis. They just don't go around talking about it, and the democrats like to lie about what the IRS statistics say to make it look like there are all these undeserving rich guys running around stealing the IRS blind - which isn't the case.
Many large companies, for example, are under permanent audit, and many even have permanent offices devoted to the IRS and to the various state auditors that continually nip at them like sandflies at the beach.
Finally, the era of the classic "tax opinion" died about 20 years ago. That was the era when one could get a tax opinion that was based on a dodgy set of facts, or a description of the facts that was not really in accordance with economic reality, and the opinion would then generally only address one isolated part of the facts and would, for example, ignore application of the step transaction doctrine.
The IRS went after both the wealthy who benefitted from those opinions - primarily because they would claim to be exempt from penalties for underpaid tax because they had a tax opinion that gave them reasonable cause for the position they took - as well as the advisers who were giving those opinions out, sometimes like candy (I am aware of a practitioner who had a dodgy TiC opinion that he had written once, and which he would then have a junior associate fill out the name of the new client, change the names of the entities involved, and issue it for a fee of $20k or so; he no longer does that, and I believe that the two or three firms he was doing that at are still paying off some of the fines that were levied on the firms for that practice).
And the simple fact is, if one is a wealthy person with cross-border investments, there is a whole heck of a lot more ambiguity in how the tax law applies to some of their investments.
Very simple case: how is a German GmbH & Co. KG classified for U.S. tax purposes? Is it a corporation, a partnership, a disregarded entity?