I work on the GNU Guix project, which can do all of these things. Additionally, with Guix, I have access to a configuration management system that can create disk images, VMs, and (in a future release) containers (replace Chef/Puppet/Docker), a tool for quickly creating isolated dev environments without polluting the rest of the system (replaces virtualenv and Vagrant when combined with a VM/container), and more.
I'm convinced that more featureful package managers can and will solve a lot of our software deployment problems, and I'm also convinced that simply layering more tools on top of a shaky foundation isn't going to work well in the long term.
I get what you're saying, but the way you've phrased it makes it seem like it wasn't intentional when in fact before immutable git-style packages were discovered, you were forced to choose between packaging that works well for developers/ops and packaging that works well for end users.
Debian is the best example we have of the latter, but it's a mistake to say they did a bad job at making ops-friendly packaging. They are solving a different, mutually-exclusive (until recently) problem.
With a bunch more elbow grease and polish, the nix/guix approach allows us to have the best of both worlds, but this is a very new development; arguably it isn't even "there" yet.
s/well-developed/widely-used
Just because a package manager has a broad user base does not make it excellent nor well-developed. pacman[1] user base is far smaller, but (IMHO) it's a much more refined package manager than apt or rpm.