they have their wedding in special reception rooms or luxury hotels because their houses is too small for 100 people
But isn't this the case in other countries as well? In Finland people rent a place for the reception because no one's house is big enough to host the entire family! I don't think I've been at a single wedding that was held at someone's home... I have never been at a Japanese wedding but I'm quite sure people have just as lavish weddings elsewhere, too. The thing is, though, that you don't have to pay hard cash to participate - atleast in theory ^^; But I think in Japan people give money at funerals, too...?

In Finland it would be considered be a bit thoughtless, maybe, to give money because it doesn't show any personal touch to your gift. So, in a way you're not required to give the couple a lot of money, but it goes without saying that you have to spend more then 10 euros on it. The amount on money you spend on the gift also depends on how closely you're connected with the couple, so this is another interesting difference because in Japan all fo the guests give the same amount of money?

Nowadays most couples have probably been living together for quite some time already before getting married or atleast lived by themselves so the more trditional gifts like china, kitchen appliances or bedsheets are pretty useless because they probably already have them. Also, I think that due to globalisation the wedding ceremony is starting to look atleast superficially the same no matter where you go. Though I think that even though it may superficially look like a "Western wedding", the older traditions are still under the surface somewhere.

Furthermore, considering the value of your reputation (face) in Asian countries, you have to throw up a great party, right? I remember one wedding I attended here in Finland where they didn't have any special foods and people still remember it even though it was years ago. So if you have a wedding, it has to "go right" here, too

Maybe the expensive weddings have something to do with the modern generations as well... I don't know about japan, but when my parents got married in the 70s, they got married at a court house on their lunch break because it was a cool thing to do. Maybe people are into fancy clothes and throwing rice again Not to forget the fact that living standards have changed.