How is that a "loophole." Multi-national structures seem like a necessary facet of the tax code. And the listed strategies don't seem to take advantage of obscure provisions, but basic mechanics of the tax system: deduction of costs from gross revenues, etc.
Take a closer look at the sections on hybrid entities, treaty shopping, and transfer pricing. There are loopholes wide enough to let tanker ships pass.
"loophole" is a word for "a completely legal tax maneuver I don't like"
Worse, it's often a work for "a completely legal tax provision I don't understand."