I am not too sure I understand. To clarify. Blizzard did not know when the next-gen consoles were coming out at Blizzcon and then literally the very next day afterwards AMD (the business making the next-gen consoles) told us exactly when the next-gen consoles are getting released. It was almost as if AMD overheard Blizzard saying this and decided to announce it.
I'll place a small wager that Blizzard ditches the idea of making D4 for the PS4 and XBone and announce that it will be for the next-gen consoles instead.
You could tell the Blizzcon streamers were surprised when Blizzard said D4 was for the current consoles. The PS4 barely runs D3, when the screen gets busy the frame rate goes to hell. Also, you can see the frame rate drop in the demo when the characters crawl out of that hole and have a gander at the larger area around them. Note that those machines at Blizzcon that were running the D4 demo apparently had 2080 ti's. Doing the math there is no way D4 could run on the current consoles without some serious sacrifices.
Anyhow, the next-gen consoles will likely have 8 core zen chips in them. This is what they'll likely need to keep the console experience on par with the PC.
I thought the whole timing thing was uncanny though, to say the least. That was the point I was trying to make.