I don't understand how you can say such a blatantly false thing. Modern consoles have more than 4 cores available, do you really think we would let the other 3 go to waste?

Large games will use all cores, our game uses 32 cores if you have them, we solved a bug because 1 guy had such a machine and reported an issue. 1 guy, from the public, and we fixed it the next update!

But no, developers don't care, we don't even like games! In fact, we hate games! Please don't enjoy our games!

This is changing very rapidly with the introduction of the low-level APIs like Vulkan and DX12 that were designed to scale on multicore systems. On those titles we've been seeing much better use of multi core resources than we saw on previous generations [0][1]

[0] http://www.pcworld.com/article/3039552/hardware/tested-how-m...

[1] https://imgtec.com/blog/vulkan-scaling-to-multiple-threads/

That's also because a 10 core chip takes a significant hit on single core performance over a 4 core one.

It's also quite likely that spreading out over more cores would be counterproductive. Many problems are not parallizeable indefinitely.