So it's actually moving money! And you need a reason to move money from one company (in the US) to another (in Canada). Call it sale, call it IP licensing...
The context was "If I’m a Canadian software company that does most of its sales in the US through an American subsidiary (not uncommon), the way it works is the American subsidiary pays the Canadian company back for the sales of the Canadian company’s IP."
The IP production occurs in Canada where the R&D departments exist and salaries have to be paid and the US subsidiary company pays to the Canadian parent company.
They cannot just "move all revenue back into headquarters' coffers."
By forcing all revenue to go through a single point (the headquarters) it's much harder to establish fake licensing like Apple Ireland's.
But I don't think that the meaning of "forcing all revenue to go through a single point" is clear at all.
From the point of view of most countries sending money out to Cupertino wouldn't be an improvement over sending it to Cork if that still means that they don't get to tax it.
> Otherwise the money would never get back to Canada and I wouldn’t be able to pay my developers!
It doesn't have to be paid for the right to sell the IP. You can just move all revenue back into headquarters' coffers, and use it to finance the various cost centers. Just write the law so that it cannot be called a sale.