Earlier quoted context omitted.
I think the biggest flaw is that the Big Mac you are served in Switzerland is not really the same Big Mac you are served in the US. It's a cute form of comparison but indeed should not be used as a policy tool.
I actually eat McD's specifically at least once while traveling internationally to see how much it changes. Anecdotal but its been my experience the core items taste and appear strikingly similar everywhere, and that's ~10 data points across the world.
I ask because I didn't get around to it; there's just too much good food in Japan and I wasn't there long enough.
But I did have a Wendy's burger, and I can tell you: it's not the same burger you get in the States. It's much better. For a given ingredient, it will be inadequate in the US, in Japan, they are all food, like you might get from a bistro.
That made me curious about McDs, but not curious enough to blow an entire precious meal on it.