Back into It - the dilemma

I went to this wedding this past August. Alex and I flew to CA, got a car and a hotel room for a weekend and got to see my friends from college. We had a great time. Alex fit in with "the boys", as the husbands are called, and I got to see my girls and have a blast catching up. Here's the dilemma. I have yet to receive a thank you note for either the bridal shower gift that I sent for the shower, or the wedding gift I sent before the wedding. While I am assuming that all things were delivered, I would like some acknowledgment of the gifts that I sent. I am sure she has my address, because we received the wedding invite in the mail in her writing. I think mostly I am annoyed at how dumb this whole thing is. We spent hundreds of dollars on short notice to get to her wedding and to be there with her when she married her husband. I even dragged Alex to all of this, on his birthday, nonetheless. While I realize that the small gesture of a thank you card cannot possibly "pay us back" for the amount of time and effort we put into coming to her wedding, it's a nice gesture that acknowledges all that we did and all the hoops we jumped through to get to her wedding. And to have not sent anything for over four months after the wedding, it just seems a little rude. I know that etiquette says to wait six months, but I just think it's likely not it the mail and will not be in the mail. Advice to all you planning parties, weddings, etc: appreciate your guests and the sacrifices they've made to make it to your parties. And send prompt thank you notes.
And this concludes my thoughts for today :)