I don't even think this has anything to do with Sony. It's just that Tekken 6 didn't sell too hot on Xbox 360 and that was with a massive install base. The X1 install base is considerably smaller than that of the 360 back in the days, so sales would logically be also fewer. Should be something like half a million maybe. Could very well be possible that Namco just doesn't think the port is worth it.
Official member of VGC's Nintendo family, approved by the one and only RolStoppable. I feel honored.