Wow, this is really interesting. Soooo, because "bridezilla" decides to have an extravagant reception, all her friends and family should give huge amounts to "cover their plates"? And if she decides to have a small receptions with punch and cake they (the bride and groom) only "deserve" a $15 or less gift, since it probably wouldn´t cost more to "cover your plate".
There are no wedding here, that I've ever heard of, with punch and cake. What you consider extravagant is probably an average wedding here. And it's not about what the couple expects to receive, it's what a guest feels the need to do, because that's just how weddings are done here, for decades and decades. Plus, keep in mind that $250 does not equal $250 in other areas. Heck, the average home costs $500,000!
i doubt housing values or income plays a large part in it. i suspect it's simply an accepted practice in certain regions that some embrace and choose to do-while others go along because they perceive it as expected of them.
the area we moved from in northern california was far from plush and starter homes were bare minimum 500,000 (nothing fancy and often over 30 years old and in need of major repairs)-heck, in napa where i grew up the current low income home ownership program defines low income housing as ones that sell for as much $532,000-and those can be total pits.
weddings run the gamut from cake and punch affairs to entire wineries and high end b&b's being closed to the public (one popular venue specializes in re-landscaping their floral garden weekly to match that weekend's wedding colors, others require a minimum of a 4 day rental periods preceding the wedding so that delivery and catering trucks can be timed such to least disturb adjacent property owners). the venues alone (no chairs, no tables-nothing, just the ability to hold the ceremony for a few hours at a particular site) can run $6000-$15,000, so a cake and punch wedding can start around $30,000. despite all these expenses it would come as a shock to anyone who lives in the region to contemplate ever basing their wedding gift on the per person cost of hosting these events.