Anyone who's ever gotten married will tell you that weddings are very expensive. $4.5MM is a couple of orders of magnitude above average, but not out of line - what else should they spend their money on if not a declaration of their mutual love?
Snort! My wedding cost less than $100 US. (Now if we had "fuck you money" like the individual in the article, my wife could have possibly spent 6 figures on the honeymoon instead of road tripping and budgeting.)
Two of the most expensive weddings, ($200K+), I've been invite to or a groomsman in, both ended in divorce within 2 years.