You know, people can spend their money on whatever they want, and on one level, well, who am I to judge, I own three ballroom dresses right now, costing EU 290 (about $450 US after shipping from France), $2900, and $4800. Got another one for sale I paid $2600 for, asking $400 (they depreciate worse than cars, and it's old enough it's not very stylish--I still wanted $500, but $400 is what the lady trying it can pay, and it meets some special needs for coverage she has, so better she use it than it hang in my closet over $100. Three other dresses I've sold cost a total of $6600 to buy and I got a total of $1400 selling them.) So yeah, the price tag ITSELF doesn't really shock me, and when I total up all the things I've bought for my non-showing, non-jumping, hacking-around-the-farm OTTB (a saddle, a new bridle I didn't really NEED, a new halter and nameplate ditto, something like three bits, a blanket even though I don't clip him "just in case", ten different kinds of treats, new grooming things I don't need but seem like a good idea, supplements for this and that, electrolytes for hot weather...) Yeah, it's not THAT much money all told.
OTOH, the reason gowns cost so much is they're labor-intensive to make and stone (they're not "Beaddazzled", they're glued-on flatback lead crystal-the most expensive gown has about 4300 on it, plus handsewn sequin trim) and are made of yards and yards of materials that are a royal pain to cut and sew. I will pay someone to do all that labor for me. The "cheap" French dress I stoned myself and it took about 10 hours and only involved about 2000 stones--that's a lot of my time. (And tears, and frustration, and gluing my fingers to the stick I use for stoning...)
A functional saddle pad? *I* can sew that. Slapping a Gucci label on it does not make it worth THAT much more to me.