No. That would imply Bethesda (Assuming Fallout 4 will be made by Bethesda. Assuming Fallout 4 is coming out, since there has been no confirmation by anyone aside from rumours and implications) would have signed an 'exclusivity contract' with Microsoft. Which they would never do, since all their games sell better on the PC than any other platform (For obvious reasons). I could somewhat believe if it was rumoured that they might forgo a new Fallout game on a PlayStation, since those always seemed riddled with glitches at first, but going just to the Xbone and leave out their main selling market? No.