As for PPC, it will fly as all nextgen consoles, PS3, Xenon and possibly whatever N will put out will depend on it.
So pracitcally hundreds of millions of households will have ppc equipment - even though they would not be aware of that. It is upto freescale, ibm and partners to make that fact publicised enough.
Will that change the desktop market? Apart from price drops possibly no, since there are way too many applications that must be used in everday life and porting won't happen overnight, it is not a simply matter of recompilation, not to mention people who actually pay for software will not throw away thousands of dollars worth of software investment overnight and we are just talking about households, not companies.
If feasible emulation would happen, like ppc cpus with dual cores running x86 code natively without any drawback, the desktop market situation wold drastically change too.
We'll get back to this topic in 5-10 years