I work at Continuum using our Python distribution (Anaconda[1] and Miniconda[2]). We sell it as the Data Scientist's answer to python, but as a sysadmin, I really think it is the answer administrators have been looking for. It installs into one directory that can be blown away if needed. It provides virtualenv-like environments except it you can isolate different versions of python or any binary. You can "activate" your environment, just by setting your PATH to find the env's bin first.
The conda package manager installs binary packages, so you don't need to compile c-extensions on each machine. Conda allows you to build all of your packages for each arch. Binstar is our alpha package hosting service that lets you host packages and it has a multi-platform build service (super-alpha). And you aren't limited to Binstar if you want to host your own repos -- the commands are built into conda.
If you want to distribute non-python binaries, you can do that as well. I'm using conda to install node and node packages. I really like using conda for node binaries, because I can build them using npm and then I have a way to push versioned node binaries to production. (Internally, we've built most of the R packages, postgres, mysql, mongo, nginx as conda packages to provide non-root users a way to install normally root-only software).
[1] Anaconda: http://continuum.io/downloads [2] Just python: http://conda.pydata.org/miniconda.html#miniconda
And then you want to install a new Python side by side and you sort of do that but /usr/bin/python still points to the old version and you have to be explicit with /usr/bin/python2.6 in your scripts. But then some scripts will work and some still don't and you make /usr/bin/python point to /usr/bin/python2.6 and now you really broke yum.
And all you can do now is hate python because it gave you all these problems.
At least, with java, no one even attempts to use distro package tools to manage libraries, packages and dependencies. Can you see a sysadmin using a syslog replacement implemented in java, requiring java8, along with a webserver only running on java5?
With python, some tools (those big enough to be packaged) are no problem. Some random tool from pip -- not so much -- now you have to patch that python binary, those python dependencies etc... and not just track security.your-distro.org.
It is certainly possible to deploy your system in a similar way you deploy your apps (take on 100% of the burden of maintaining the whole thing) -- but normally you want the "system" to be a stable foundation on which to erect your rickety duct-taped mono-jvm-python-ruby app-stack with the help of puppet/chef/cfengine/salt/ansible... you don't want pip/hackage/gem/npm to manage your system. You might trust it to manage a single application.
You've still got to provision those, but, well, they're individual and isolated and tend not to go hammering into one another. Other than consuming all available system resources.
Oddly: IBM got this right with VM ... 40 years ago?
It used to be a major PITA with Perl. I've run into it with Ruby (and the proposed solutions are even more horrible: RPM).
And yes, Devs absolutely want teh neu hawtness.