>do we still need things like VM, paging, and segmentation?

Yes. To begin with, on modern processors, paging is tied with the memory protection system. Memory is protected on a per-page basis. Memory mapped files are implemented through paging. There's also backwards compatibility. Virtual memory allows 32-bit applications to have their physical memory located anywhere. Without that, we'd have to ensure that they reside below 4GB. Programs would start up slower as the executable would have to be relocated every time. Additionally, it's hard to imagine a hypervisor that doesn't use virtual memory. Virtual memory allows hypervisors to present a unified address space to their guests; no matter how fragmented physical memory gets.