True but actually less significant than you think. With the caveat that the diamond should not be insignificantly expensive the reactions to engagement rings fall into one of two categories
a) the girl is a "nice girl" and is more than happy that the finacee got a ring that was even better valuable (I've one singaporian friend that actually had her fiancee take his ring back and buy another one from singapore - not because she wanted a bigger one but she wanted him to get a better deal (I think it ended up being a bigger diamond but that's not what she was angling for))
b) the girl wants to have a bigger ring than her friends in which case it's also a win.
The actual value of the ring is more of a "hygiene condition". Once it costs "enough" then to someone who actually cares (most girls are just happy with getting a hubby) what actually matters is what it's perceived to cost and a fiancee who can deliver bigger, delivers bigger!
a) the girl is a "nice girl" and is more than happy that the finacee got a ring that was even better valuable (I've one singaporian friend that actually had her fiancee take his ring back and buy another one from singapore - not because she wanted a bigger one but she wanted him to get a better deal (I think it ended up being a bigger diamond but that's not what she was angling for))
b) the girl wants to have a bigger ring than her friends in which case it's also a win.
The actual value of the ring is more of a "hygiene condition". Once it costs "enough" then to someone who actually cares (most girls are just happy with getting a hubby) what actually matters is what it's perceived to cost and a fiancee who can deliver bigger, delivers bigger!