> now a process has started to corner it in its new domains.

The networking/communications domain is far from a "new domain" for PPC. It's been going strong in that domain since the mid-1990s:

http://en.wikipedia.org/wiki/PowerQUICC#PowerQUICC_I (1995)
http://en.wikipedia.org/wiki/PowerPC_400#PowerPC_403 (1994)

The PPC had its debut in the desktop computing domain in March 1994, so it started at about the same time in both domains.

> Freescale isn't immune to costs, and why keep developing two
> architectures, costing twice as much, if you could manage all your
> needs with just one?

Because Freescale's need is to get money from its customers in exchange for products, and (some?, most? of) its networking/communications customers' current and foreseeable-future need is being offered (existing and new/better/faster) Power Architecture products for several technical reasons (see also what itix said).