The problem can be roughly stated as: For a company registered in country I, selling product/service in country F, with inputs licensed from and/or created in countries N, U, B, G, A, and C, and costs incurred in a potentially different set of countries, what's the amount of tax due to each country represented in the graph?

There are many simple answers to that question; who gets to decide which simple answer is the one enacted? Countries F, I, and U are likely to disagree on which simple answer is "best", which is why we rely on laws and courts to frame and adjudicate the issue.