Hmm, I wonder how Eyeballs ISP (TCL and TCNZ) would re-act to that situation having de-peered at APE/WIX. ----- Original Message -----
Because the streaming media provider may decide to reduce their costs by hooking up to the APE and doing multicast all by themselves. That's basically what the BBC is doing.
For example, a television station could provide high-def content only to customers of multicast-enabled ISPs that they reach over APE, and standard-def to everyone else that they reach over [insert expensive transit ISP here].
Eyeballs ISPs would have pressure from their users, who want the high- def content, and probably from the television station too, who wants to pay less for transit, to enable multicast. This is exactly what's happened in the UK - a bunch of end-user ISPs now support multicast after the BBC started offering content.