PowerPC chips are being used a lot in the embedded market. Things like routers, cable modems, flight controllers and car engine controllers. These are the clients that will make sure the PPC design is still around in 10 years.
These are also the kind of buyers who order quantities that'll make it feasible to get a custom die, made to their specs and unavailable on the open market.
I sincerely hope the team has already sourced the processor. Some of these can be True Unobtanium®...
For instance, the ARM SOC powering the Raspberry Pi can only be bought in minimum quantities of one million. For the defense industry, buying one million PPC chips isn't a problem at all, even if they need only 10.000. A typical dual core VME board will set the army back around 5.000 US$, excluding support. And that's for an SBC, so just a single PCB with a maybe 1 GHz processor and 512 MB ram. Not what we would consider "high end".