F-Commerce isn’t working, and the more Facebook tries to fight it, the more it seems obvious that the social network is not a home to retail. Facebook is normally pretty quick about killing experiments that don’t work. (It’s first iteration of social commerce, Beacon, didn’t last long.)

But not with Facebook storefronts. Watching the struggle reminds me of the moment in Mean Girls when Regina George snaps at her sidekick to stop trying to make the slang word “fetch” happen. F-commerce is simply not going to happen.

Yesterday Bloomberg reported that Gap Inc., Nordstrom, Gamestop and J.C. Penny have  shuttered their storefronts on Facebook. They’re not small potatoes retailers who don’t know what they’re doing, these are savvy brands who gave F-commerce a shot and realized the social network was, in the words of a Gamestop rep, “not a place to sell.”

The most commonly supplied reasons for F-commerce’s shortcomings are pretty obvious: People aren’t used to buying on Facebook. They don’t feel comfortable putting credit card info into a social sharing site. They aren’t there to shop–they’re socializing. Shopping doesn’t fit into the other Facebook actions of liking, sharing or commenting.

For each of these reasons, you could argue that it’s only a matter of time. People had the similar doubts about e-commerce when it first started out; now it’s a $680 billion business. Facebook and F-commerce hopefuls could try to force acceptance. But it’s been three years–Facebook’s first storefront, 1-800-Flowers, launched in 2009. As of last year, only 7% of brands with a Facebook page had set up shop. Even Pampers, which Facebook touts as a shining example of F-commerce success, doesn’t list most of its products on Facebook.

I would argue that the biggest problem with F-commerce is not whether people will accept it, but the massive costs to the retailer. Any established brand has already poured piles of money into the development of its website, as well as ordering software and inventory operations that go along with it. They’re large scale operations. Adding another location to constantly update with new inventory, take orders and process payments in a way that’s integrated into the existing system is not cheap, and if the volume is low, I don’t see why any retailer would keep the store open.

Beyond discovery–which brands have already figured out via their fan pages–F-commerce offers no value to the user or to the brand. I’d rather shop on the company’s website, where the brand has taken deliberate steps to create an experience and present its products in a way that best suits them. A blue Facebook bar with a bunch of Angry Birds ads cluttering up the right side of the page don’t really fit with any brand’s aesthetic. Opening in a new tab may even save me a click, as the path to the F-commerce storefront app is not always a direct one. (They exist in a special “shop” app on the brand’s Facebook page; Facebook encourages the retailers to direct users to their Facebook store page via display ads).

Retailers are right to stick with discovery and engagement on Facebook. As a marketing tool, social media works wonderfully–revenue per click from shoppers arriving via social media links is $5.24, versus the $3.18 per click spent by email shoppers. As a shopping cart, it’s empty.