Everything comes to Steam eventually. The FFXIII trilogy might end up in Valve's box as well, if this screencapped image has anything of worth to say:
A recently launched portal page for the FFXIII series in Japan highlights the company's new DiveIn streaming system, whereby customers will be able to essentially stream the games to your smartphone or tablet, and play the game on the go. Interval fees apply.
While the DiveIn logo is present and encountered for in the above image, for some reason Valve's Steam logo is there as well. An indication of the three games heading to PC? Will Lightning strike again? Will she ever leave? Will mods make the games fun? I dunno, but if it happens, it will follow FFIII, FFVII, and FFVIII.
Siliconera