Uh, yeah it is just about the origin. You could fly in all the ingredients used in the Champagne region to an exact replica of a Champagne winery in the same climatic zone manned entirely by French immigrants who formerly worked in an actual Champagne winery, and wouldn't be allowed to call it Champagne.
One of Europe's prime exports is its "culture". People pay a lot of money to vacation in various European locales to taste "authentic" whatever where it was originally produced, even if they couldn't tell the difference between it and something made down the road in an Illinois industrial park. Without location-based brand enforcement those locations would lose a big income stream, never mind the "authentic" mark-up they get on their exported products.
As for cheddar, you can buy fancy imported cheddar at Walmart, never mind Whole Foods and the other upmarket chains that will have entire dedicated sections to fancy cheeses imported from all over the world. The reason it got the reputation you describe is simply cost. Same reason Folgers and Maxwell House are still on the shelves despite the insane variety of better coffee available these days.
For it to be "just about the origin", what you describe is not enough. You'd need to establish the inverse as well: that you could bring in the raw materials from outside the region, use a different production method, and still call it Champagne. That all that matters is the production region. And that's demonstrably not the case.
The origin is the only factor that has no theoretical impact on the quality of the finished product. It's a purely political poison pill for any would-be producer, which means at the end of the day it is all about the location.
If I offered you a perfectly functional car, but added an unnecessary kill switch that prevented you from starting it without my express and arbitrary permission, would the deciding factor in your purchasing decision be the build quality of the engine, or that kill switch?
One of Europe's prime exports is its "culture". People pay a lot of money to vacation in various European locales to taste "authentic" whatever where it was originally produced, even if they couldn't tell the difference between it and something made down the road in an Illinois industrial park. Without location-based brand enforcement those locations would lose a big income stream, never mind the "authentic" mark-up they get on their exported products.
As for cheddar, you can buy fancy imported cheddar at Walmart, never mind Whole Foods and the other upmarket chains that will have entire dedicated sections to fancy cheeses imported from all over the world. The reason it got the reputation you describe is simply cost. Same reason Folgers and Maxwell House are still on the shelves despite the insane variety of better coffee available these days.