If we needed sparkling wine daily we could probably adapt our taste and production methods to make it anywhere in massive quantities.
If you live in Reims it's a 20~30 min drive to a producer, from Paris it's roughly a 2h drive. In 2h you come to the producer's winery, taste a few of their production, and come home with a box of 6 or 12 pretty good bottles that you got a fairly low price (20 ~ 50 euro a bottle is realistic).
You can drink them in a 2 or 3 month span, and do the trip again to another winery.
For these few millions of people, Champagne is not _that_ much a luxury, nor a rare drink, yet it still tastes pretty good. National Champagne consumption is healthy and varied, and Champagne is still in competition with all the other crazy good wines of all sort (including other sparkling whites from France, Italy, Spain etc.).
There is definitely hyped brands, and Champagne getting out of France is at such a markup that it makes it harder to go for taste only ignoring the rest of the cultural markings, but I'd argue wineries from the Champagne regions are still extremely good at their craft and also live in a competitive environment in regards to taste and quality.
And I don't spend so much money because I chase the expensive bottles, it's because the prices for good grower champagnes have exploded in recent years. Bottles I could previously easily find for 150 are going for well over 500 now.
>It has to come from Champagne and be a bit expensive or there's no point.
Not at all, for example Franciacorta Annamaria Clementi is an excellent sparkling wine (well, Franciacorta, made using the same methode traditionnelle as Champagne) that holds up well when compared to decent champagnes. (Although direct comparison is a little tricky given the drastically different climates, you're best off picking best vintages of each and comparing them)
If we are speaking in extremes, then yes, the nicest bottle of Champagne blanc-de-blancs might best the lot. However, that would indicate that we have largely fallen for the marketing trick. Champagne as an AOC has paid a lot to keep it exclusive. Meanwhile, neighboring vignerons with terrific bottles are locked out and can't sell their bottles for half what a mediocre champagne goes for.
Going by this assumption, the neighboring vignerons have zero incentive to try and make a product that could compete with decent Champagne. A winemaker selling their bottles for 500 can invest much more money per bottle than a winemaker selling their bottles for 50.
So even if it was all marketing at some point, it ends up being a self-fulfilling prophecy.
What is the point of it being expensive? Seems easier to log into your brokerage account if you want to remind yourself you can afford expensive things.