Recovery won't work huh? Are you pressing VOL UP + POWER after you enter recovery? Normally you just get a black screen until you press VOL UP + POWER multiple times. But if you are flashing the full SBF as instructed, recovery really isn't necessary...
How could it be a hardware problem? Good question. These devices have thousands of tiny intricate parts. I won't pretend to be some kind of expert, but random failure is always a possibility. It is rare, but the fact that this whole issue happened seemingly randomly would suggest that a Hardware failure might be the case.
Now, Since the Moto X has only been out for about a year, consider the possibility of getting a warranty replacement! The USA models carry a 1-year warranty. You might check with Moto to see if your XT1052 variant does as well.