I guess MIPS and PowerPC are still around somewhere, but it's definitely a lot less common to see them these days. For example, it used to be that every Mac came with a PowerPC, and so people were aware of the issues that chip had. Nowadays it's rare to find a programmer experienced with anything but x86. That was really Eric's point when he made that comment.
It's less common because they're hidden inside other equipment. E.g. my RAID cards have PPC cpu's; my set-top box used to be MIPS. They're both licensing hundreds of millions of cores a year.
