$1,000 in CPU is nothing when in one server you are spending $32,000 on RAM and even more on disks.
Plus, if I have 16 more cores I'm just going to buy even more of the two, sometimes I can't fit any more in the server so I can't increase my density if I wanted to.
I'm not sure why you need 3 Terabytes of RAM in every server. Even if you were to replace every single application on your OS with a JVM based one (including things like bash) you wouldn't meaningfully hit that limit. If you have an application that does indeed need many Terabytes in the same address space then you probably have a very small number of servers. No one runs a 1000 node cluster where each node has 3TB RAM.
Plus, if I have 16 more cores I'm just going to buy even more of the two, sometimes I can't fit any more in the server so I can't increase my density if I wanted to.