It was a PR move, but it also could have worked just fine had the phone been a bigger success in the U.S.. They didn't export any American-assembled Moto X's elsewhere, it was strictly a plant for sales within the USA.
Sadly, this seems like an ill-planned move. Moto may have a brand history, but it's a fairly pathetic history, filled with terrific hardware but abysmal sales outside of the major carrier-exclusive products, mostly Verizon's Droid line - and because of that, terrible brand recognition. They are known for quality and sturdy products with antenna/radios that typically outperform the competition, but it takes more than that.
I thoroughly expect a second and third Moto X to really rock out in sales, so long as they do the marketing right and have the important bits solid and ready for launch (like the actual product assembly and ordering system - it's still been lackluster under load).
The Moto X is a fantastic device - but this was really the first time Motorola ventured out with their own brand approach, and they weren't prepared and didn't sell up the strengths as well as they ought to have.
I think they'll make bank on the low and mid-end markets, but they need to really establish a brand wrapped around the flagship X series, and hopefully the next X has the internal guts to not scare away those who worship specs. I was extremely hesitant and it took awhile to convince me, notably a sale and frustration finally boiling over with my VZW Galaxy Nexus.
I think they may need to really establish a Moto X and Moto XL deviation, as perhaps half of the fail in sales has been an issue with some people wanting to focus on the phablet-size phones. I can't stand requiring two-handed operation - I can and do use two hands with my Moto X, but it's perfectly at peace with one-handed operation.
I'm still pissed that Google offloaded them the way they did. Not that they sold them, that was something I figured they'd do in the long run - but to a Chinese conglomerate, after all these years as an independent American corporation? More than anything, that's just a nasty slap in the face. Now the entire market is essentially an Asian market, especially as it concerns the American dollar: Nokia and Sony Ericsson just don't sell strongly in the American markets, though there may be an upward trend to be had as they expand and change their business strategies a little. Granted, Sony Ericsson (or Sony Mobile, I think) is basically Japanese-owned, though really a Swedish brand.
Hopefully Lenovo does us right and keeps the American nature of Motorola, instead of entirely incorporating their brand and product into the conglomerate and ultimately exerting full control over brand direction and product portfolio.
Ultimately, I think Motorola just needed another generation of product to see enough revenue to sustain the American plant.