I think it's not the provisioner's responsibility to provide the tools (much like Vagrant chef-solo provisioner doesn't install Chef for you).   I suppose this is a reasonable convenience ... but I worry that I (or others) would soon want to be able to specify a version (e.g., if you want Chef 10, you must do something like `curl ... |  bash -s -- -v 10.26.0`), plugins, etc and it could get complicated.