The somewhat simplified results of recent research, suggests, that expensive engagement rings and weddings, actually increases the likelihood of divorce. The exact cause or correlation of this is not yet understood, we just know that these things seem to occur together. One of the hypothesized reasons is that for some of these couple, the cost of the ring/wedding, contributed to the financial distress the couple as to deal with as husband and wife. While it is true that finances are at or near the top of the list for issues leading to divorce, it is also near the top of the list for issues with which stable marriages have to cope.
I have my own theories. I suspect that the show, gets in the way of the message. Couples, get so incredibly focused on having the biggest ring, the fanciest wedding and all the associated events. Then, the actual wedding service, the significance of the vows they are taking, and the reality of the commitment they are entering, gets lost in the spectacle.
Getting married is a big deal. It certainly deserves a big celebration. Just don't let the celebration, cast a shadow on the marriage, that has been created.
For more information on this research, check out this article.