It's completely dominant in the console market. That is going to change with the new generation though but if you go buy a console today, you're buying and IBM PowerPC.
That's PowerPC-based chips, not actual off-the-shelf PowerPC CPUs. Big difference.
Also, the main thing with the PS3 was the Cell architecture which was going to appear in every type of device from TVs to mainframes and make the rest of the processor industry obsolete.