Similar to the chances of Windows 8.x being commercially successful.
Right now the combined market share between 8 and 8.1 is about 12.64% with a slight nod to 8.1. That's about half the market share for the discontinued Windows XP.
Logic dictates that given the additional pain and suffering of developing a Windows 8 capable version and the hope that Windows 9 is a year or so away, it is a very difficult choice.
