I swear I had Econ in college, but I don’t remember anyone saying this so succinctly. It’s from a weird place too, but this quote hits home. It’s like population decline, but for money.
It was a truly baffling thing for an American president to say. And University of Michigan economist Justin Wolfers explained on MSNBC that things could get very bad as Trump’s scheme becomes reality. Wolfers ntoed that the idea of how much you can afford to buy with your income is called “real income.” And if real income falls, that’s called a recession. Wolfers went on to explain that if things decline as badly as Trump’s example, where someone who bought 30 dolls could only afford to buy two dolls, that’s called a depression.
Video from MSNBC: https://www.youtube.com/watch?v=sAZxLm6M_V0
GDI is supposed to be basically equivalent to GDP, so it’s not a better number to use. Sometimes the numbers diverge (see here for a discussion of this issue in 2022) because they use different methodologies to determine the number, but that’s usually a sign that some kind of measurement is off, not that there’s some kind of actual divergence in the true numbers of what they purport to measure.
And we moved away from Gross National Product/Income to Gross Domestic Product/Income because it was a better look at the domestic economy. We care more about the production/income within national borders rather than the production/income of a particular nation’s residents.
GNI still gives a slightly better measure of income which is what OP was asking for. For instance if an American gets dividend income from a foreign company that’s part of GNI but not GDP, and vice versa if a US company pays dividends to a foreign shareholder. But yeah in practice all of this will be negligible.