I am not a Jessica Simpson expert, but I did really love the Mellencamp-sampling "I Think I'm In Love With You" when I was 12, so I can attest to this: She was briefly a regular pop-star, with songs and videos and appearances on NOW That's What I Call Music!, probably.
It's such a 1999 pop song--the post-New-Jack R&B rhythm and drum sound, the slinky little guitar figures and Janet Jackson synths under the "Jack & Diane" hook, the insistently carefree amusement park video. There are no Y2K jokes or foil lounge pants, but there's also no reason to see Jessica Simpson as anything other than another pop star who is famous in a way that's only moderately reflexive. It's well-executed and harmless enough that parents would happily direct their nine-year-old daughters to AOL Keyword Jessica Simpson for free buddy icons and an exclusive message to her fans.
But even then she was never quite--or just--a pop star in her own right. She was The Wholesome Pop-Star. Writing wholesome pop is a perfectly laudable goal; it's exactly what appealed to 12-year-old me, who mostly listened to CCM and was a little threatened by Britney Spears's collection of leather bodysuits and color-matched headsets. We can debate the phenomena behind all the abstinence pledges and purity rings in contemporary boy-and-girl-pop, but after the ring is on and the pledges are made it seems consistent enough to release albums titled Sweet Kisses instead of ... Baby One More Time.
But Jessica Simpson was--even in 1999--defined entirely in relation to other pop stars. She was famous for being famous differently than Britney Spears. That's not a healthy place to proceed from, and if the rest of Simpson's music-first career is a little inconsistent--the self-consciously sexed-up Irresistable followed--that weird opening gambit probably has a lot to do with it. Christina Aguilera was about to start mud-wrestling in hot garbage; the target never stopped moving.
In that sense, going all-in on being meta-famous was a career-saving move--if you're going to depend so much on where you stand in relation to someone else's image, it might as well be yours. We're still talking about her in 2013, so it worked.