I'm not sure what bit rate and what CDN prices you used, but at these data levels I think you'd definitely want to get your own bandwidth. So even ignoring the free colocation and peering a big streaming provider can get, I see a bunch of offerings for $30-50/Gbps in the US and EU. And what percent of 8k tier users are going to be watching 8k simultaneously, maybe 10% peak? A service could use 1-2Gbps if it wanted to. There's no reason for it, but it could.