Kernel Bloat
With "VM" now the Kernel, the OS (e.g.Linux) is now in "tool-space" . Next logical step is to have direct user-space Docker-space calls for high performance operations.
(My last real coding work was using a <1Mb Unix sys5 kernel, which looks and feels like a VM container to me!) and with a 4MHz 68000 you NEVER copied when you could pass pointers!)