Maybe I'm biased, but I find it hard to believe that those 150 million (nearly half the population of the US?) would see a notable drop in the quality of their lives if their iPhones were Samsung, or Huawai, or any other non-domestic company's.
You're right in that "meaningfully improve" and "disproportionate" aren't precise or scientific terms, either.
And re: colonialism, I think more people have managed international trade without going coloniser than did, so it can't be seen as the sole origin. Needs more to germinate.
On the main issue, I'd say while GDP is far from perfect, it's better to have the measure than not. Even if it works best as part of a range of measures and not over relied upon as it tends to be in popular understandings at the moment, in my view anyhow.Temper it with more inequality stats, and also median wages vs. cost of living.
That's a really good analogy for it, thanks for sharing.