If you don't agree with it, don't go. Seriously, I don't think you "get" to enjoy the fruits of their labor, planning, and money, if you feel it's just oneupmanship, or keeping up with the joneses, etc etc. IF you're philosophically opposed, keep yourself away from that wedding.
First, it's not always the moms planning the wedding anymore. Worse, the moms whose moms planned their wedding, so the mom is just planning what SHE wanted for her OWN wedding but was denied. That's what happened with all of my friends who married in their early 20s. Their own moms' old wishes and desires were ALL over the friends' weddings. But a switch has happened, and women are planning their OWN weddings now. (which does leave a, I don't want to say generation, but if you look at each generation within a family as a layer, there's a "layer" of moms who didn't plan their own, and didn't plan their daughter's, and that's got to be frustrating).
Then you have the many many bridal magazines that people can look at and get ideas that never ever would have occured to the average person getting married. I personally developed an addiction to British bridal mags (and and expensive addiction THAT was) while engaged, and there were ideas in there from '01 to '03 that are *just* seeing the light of day in the States now...
There's the internet, where people can get ideas from everyone else! So a bride who lives in midwest and figured she'd have wedding, dance, and dinner, with very little booze if any, now realizes that other women have the reception as a dance and dinner together, have open bars, etc etc etc...
Sure there are some couples who are just in it for no good reason, but while I was planning almost all of the women (and some men) that I met on wedding planning message boards were just trying to figure out what made their eyes happy, what might make their guests happy, what might make a special day even MORE special for everyone.
If my mom were alive, and if we had still been living in the house I grew up in, I would have been ALL over a backyard wedding. Our house was absolutely tiny, but the yard was enormous and had plum trees all over, it was lovely. But that was gone. My mom was already dead, and she'd long moved from that house. Because she was gone, I could have and I *had to have* a different sort of wedding, and so I did. An outdoor wedding and reception, under apple trees in an orchard, isn't that different from the backyard I had growing up, but I also had letterpressed invitations (b/c they are awesome). Sure, the invites were fancy, sure they cost a lot (thanks Dad, which is another part that wouldn't have happened if my mom were alive), but they were gorgeous and I wanted them, especially with the red Double Happiness symbol we had on them...
What on earth is wrong with a kid-wrangler???
anyway, I've made it sound like I had a crazy shindig, but I didn't. I think it was $30 per person, we only provided beer and wine (b/c both of our dads had problems with hard liquor in the past and we didn't want it right there in their faces), but if someone wanted a mixed drink they could walk up to the restaurant and snag one, and we had a fun Irish music band (I walked down the aisle to the drumming of a single bhodran, and DH and I had our recessional to the Indiana Jones theme!)...
Was it fancier than some weddings I've been to? Sure! And about a year later we went to the wedding of a family friend (that we'd grown up with, and her mom and my mom had grown up together), it was in her luscious backyard under apple trees, it was all home-made and AWESOME and wonderful and fabulous...she had the resources (closeknit family who lived close geographically), the time, and the space to do it without having to hire a venue...
If you don't agree with the wedding, don't go. The couple doesn't need your critical eyes assessing how much money they've spent on invitations, food, drink, etc. They very likely invited you because they LOVE you, and they just wanted you there on that special day, that they are likely working hard to make special for you and the other guests...so if you can't be there in that way, stay home.