Let's face it. When it comes to enduring mysteries, it's hard to come up with something more mystifying than how Jennifer Aniston became a movie star. After all, she's made an almost-unbroken string of forgettable movies that have rarely made a lot of money, a streak that looks like it will remain intact with the release of "The Switch" this weekend. So how did it happen? As it turns out, my favorite sports columnist, ESPN's Bill Simmons, has a provocative--and hugely entertaining--theory about how Aniston has managed to remain an A-list star, despite appearing in such hapless sludge as "Derailed," "Rumor Has It," "Management," "Love Happens,"  "He's Just Not That Into You" and "The Bounty Hunter." 

Aniston's biggest hit was "Marley & Me," though it's something of a stretch to say that she was the driving force for the film's box-office triumph. Or as Simmons puts it: "They could have made this movie with Betty White playing Owen Wilson's wife and it still would have made $100 million." So why hasn't Aniston faded into obscurity, ya know, like Matt LeBlanc and some of the other "Friends" lesser lights? Here's a condensed version of Simmons' theory:

"Because of the Angelina/Brad/Jennifer love triangle, which is like Brett Favre's comeback/retirement/comeback routine multiplied by 10, but has been cruising along for twice as long. The saga evolved in various forms: the betrayal itself; the aftermath, when Aniston licked her wounds as "Brangelina" took off; her futile search for a bounce-back boyfriend; the Brangelina clan expanding; everyone feeling worse and worse for Aniston, with her finally admitting that she was still bummed out; the Brangelina clan expanding again; Aniston's weird dalliance with the much younger John Mayer, which ended when he talked out of school about her; the Brangelina clan expanding again; Aniston approaching her 40th birthday and wanting a baby; the Brangelina clan producing twins; Aniston hitting 40 with no baby or husband; Aniston passing 40 with no baby or husband. People can't get enough of this stuff. Aniston resonates with women like no other celebrity. No matter how wealthy or famous or good-looking she is, the nuts and bolts of Aniston's "tragic" story could have happened to anyone: She lost her scummy husband to a seductive co-worker. Maybe it was the worst thing that ever happened to her personally, but professionally? Godsend."

Being The Sports Guy, Simmons compares Aniston to an aging athlete (think Karl Malone or Steve Nash) who, having never won a championship ring, is desperate to finally get into the winner's circle. In fact, he theorizes that if Aniston had remarried in 2006 to a rich Rande Gerber type and had a couple of kids,  by 2010, "would anyone care about Jennifer Aniston? NO!!!!!!" Only if she made good movies, something that has so far largely eluded her. Simmons suspects that Aniston doesn't much want to make great movies, saying "she's happy being a likable celebrity with decent comic timing who plays herself in every movie (with only her hairstyle and co-star changing)."

I suspect this strain of career success/personal unhappiness runs deep in the Hollywood DNA. After all, there are loads of old-school showbiz starlets, dating back to the days of Lana Turner and Rita Hayworth, who had all sorts of similar man trouble, the only difference being that in those days, you married all the louses and had to endure a quickie Mexican divorce before you could regain your freedom. Who knows? Maybe Aniston will find Mr. Right tomorrow and enjoy a burst of later-in-life happiness. If having a successful marriage freed her from the shackles of being on the cover of US every other month, I bet marital bliss couldn't come a minute too soon.   

Photo: Jennifer Aniston and Jason Bateman in "The Switch." Credit: Miramax Films