A colleague going on 3.5 weeks vacation to Europe with his wife in a few months time told me he has budgeted $30K for the trip. That's $1200 per day!
While I would rather spend 40 weeks with a spouse on a trip for $30k instead of just 2.5 weeks (unless I had insane buku bucks and no other way to spend it), when you stop and add things up, it isn't too terribly hard to spend that much - especially considering they're traveling in peak season
Somewhat higher-end hotel - $200/person/day, plus tax (consider that even a modest LaQuinta Inn in Chicago can easily run $160/night plus 14% tax)
3 course meal with wine at nice restaurant - $100/person/day ? (maybe more)
Breakfast at hotel, lunch/snack in town - $50/person/day
Flying over from the US, peak season, plus 2 flights while in Europe - maybe $2,500/person with taxes?
The above comes to over $500/day per person, and that's without any museums/activities, gifts, tour guides, or transportation other than flights. Just one piece of jewelry as a momento could easily run a few thousand.
Sure, most on this forum would find ways to trim that down...but considering that the average person (even those without the means to spend that much) simply impulsively buy what they want rather than minimizing their spending, it's not impossible to spend that much when traveling in peak season.