Cell phones are commodity items, not modular case+fans+CPU+GPU+PSU+motherboard+X+Y+Z purchases. You can (and some markets do) fit $100k of product into an 8'x8' stall and have plenty of space left over. Cell phone plans are perfectly centralized, and can be purchased online or over the phone. At the same time, online reviews are essentially the only reasonable place to seek unbiased advice, and are plentiful.
This is a market demand that, while it may have reason to exist, could be filled by 10% of the current locations selling cell service & phones. Instead, T-Mobile needs a storefront, Verizon needs a storefront, Apple needs a storefront, and half a dozen adjacent electronics stores or electronic departments sell cell phones on the side, in every large strip mall or indoor shopping mall in America.
In a functional market economy, profitability is minimized through competition; It's a waste that we tolerate in order to incentivize performance. By 2013, the cell phone companies & retail established have established de facto agreement that it's better for them to plow profits into essentially purchasing large quantities of well-manned empty space in every major electronics store in the nation, rather than lower prices or improve their infrastructure.
Especially when mobile phone subsidies is becoming a big part of their income stream. That's like crack to them now, hard to turn away from that.
But if this DIY/3DP movement is going mainstream in the coming generation then they need to make a big move. Imagine if Radio Shack makes a comeback consolidating the parts market by buying up the likes of Sparkfun, Quirky, and IndieGogo while partnering with Digikey for retail distribution.
Then imagine they developing mobile apps that can quickly identify and give contextual information to individual parts so the average consumer hobbyist can be empowered to chase their dreams.
I would bet on that instead because empowering others will always be a better purpose. Otherwise they're going down like Sharper Image or Best Buy because Amazon is here coming to eat their lunch.