Does etiquette not exist anymore?

I know that wedding planning is exacerbating  the situation, but I have also suspected for years now that etiquette is slowly ceasing to exist. There used to be the days when the etiquette "rules" were ones people practically lived by - like in the the June Cleaver 1950's. Now in the days of email, texting and instant communication, grammar and spelling seem to have gone out the window along with etiquette and manners. We are under the 30 day mark until the wedding, the deadline for RSVP's to our destination wedding has long passed, and we are still trying to get definite answers out of people (including, ahem, some of the groom's only relatives - who are not elderly!) on wether or not they are coming. We sent out the Save the date's a year before the wedding to give people, especially our friends who might not have the means but we knew wanted to come, time to plan, save, get time off, etc. Now we are having a couple (groom's friend and his girlfriend, in their early 30's) who already RSVP'd, my dad spent weeks finding them a hotel room cheap enough so they could come, booked it for them, and now they are saying they don't know if they can come because they have decided to go to Vegas at the end of this month. Okay, they are perfectly within their rights to do so, but it still does not excuse the rudeness of the situation! Sorry to vent, and while I am by no means perfect, I think manners and etiquette should still have a place in this world! Any one else shocked at the lack of proper manners these days??