So, somewhere, can't remember if it was this thread or not, someone talked about how most of the country female artists seem to have a drop off in popularity around their 4th album. Since this is Carrie's 4th album, I went to wikipedia to do a little research on Faith, Martina, Shania, Trisha, etc to see if there was any kind of effect on their popularity after the 4th album. Here's what I found based on RIAA certifications:
Faith Hill: Album #3 Faith, 6x Platinum; Album #4 Breathe, 8x Platinum (Cry & Fireflies both went double platinum after this)
Martina McBride: Album #3 Wild Angles, Platinum; Album #4 Evolution, 3x Platinum (Martina only had one multi-platinum album after Evolution, which was Martina)
Trisha Yearwood: Album #3 The Song Remembers When, Platinum: Album #4 Thinkin' About You, Platinum (Trisha's only multi-platinum albums were her first & Songbook Collection)
Leann Rimes: Album #3 Leann Rimes, Platinum; Album #4 Twisted Angel, Gold (Boy, this was a tricky one. Leann had two compilation/special albums after "Blue". Her true second album still had 4 covers on it. What I thought was her 4th album, "I Need You" was really a collection of B-sides and promo tracks to fulfull her contract and only went Gold. While "Blue" went 6x Platinum, nothing since "Leann Rimes" has gone platinum except for a Greatest Hits album.)
Miranda Lambert: While Kerosene and Revolution have gone Platinum, she has no multi-platinum albums certified.
Reba McEntire: Reba had a LOT of albums in the early 80's before she became popular. I decided to count "Whoever's In New England" as her first album, as it's the first that most of us have ever heard of, then chose the 3rd and 4th album from there. So, with that: Album #3 The Last One to Know, Platinum; Album #4 Reba, Platinum. (Since then Reba has had several multi-platinum albums, with the highest certification for a regular studio album being 4x Platinum for "For My Broken Heart" which was released in 1991.)
Shania Twain: Album #3 Come On Over, 20x Platinum (was this a double disc?); Album #4 Up!, 11x Platinum (Special case, of course, since she hasn't released anything since Up!)
I left out compilations such as greatest hits and Christmas albums. I'd be happy to look up anyone else, but those are the ladies that I feel we can best compare to Carrie's career as they have been around a while and were popular during their time. I think we can all realize just how special our Carrie is - especially in these days of lower album sales. And we can also see that there isn't any kind of 4th album curse, as Faith, Reba, and Martina all had increased sales on at least one album after their third studio release. Who knows what Shania would have done and Leann is a glaring example of a mismanaged career. The problem is that these women didn't hit it right out of the box with their first album. It took until their 3rd or 4th album for them to become incredibly popular (except Leann). Trisha seems to be a case of a great talent that isn't commercially successful, which somewhat surprised me for as respected as she is in country music. Our Carrie started out so high it was hard for her to become any more popular with successive albums especially with the decline in album sales. I personally still think we haven't seen the best Carrie has to offer and that her next album could be the one that is her "career maker" in terms of artistry. Unfortunately the decline in album sales means we may never seen SH type numbers again, but I think she could easily see a 3x or 4x Platinum album if it was the right material.
Edit: For a male reference, look at Rascal Flatts. Their highest certifications came on their 3rd and 4th albums (Feels Like Today which had several hits and Me & My Gang, which had "What Hurts the Most"). I believe Still Feels Good (2x Platinum) only sold based on their goodwill from the previous two albums. Unstoppable has only been certified Platinum and the latest album only sold 165k in it's first week. So, it seems that for most artists, the 3rd-5th albums are when they have their "peak" sales.
Trisha seems to be an artistic favorite, but not a commercial success. Leann was a novelty at 14 with Blue, but no one cared once she wasn't the cute little girl anymore (how lucky are we that that wasn't Carrie and she waited!). Miranda may be just hitting her peak with Revolution. Reba is kind of odd, as she put out so many little albums, often more than one a year, before she made a name for herself, but she has stayed popular for over 20 years, which is amazing. Her last platinum album certification, though, was in 2007 for her Duets album and before that 2005 for Room to Breathe. And Shania...well, we'll see just how popular she still is if she ever decides to come back.