Maven doesn't prevent versioning issues from cropping up, either. One common example is where dependency A pulls in library C 1.0, but dependency B pulls in library C 2.0. They often conflict, and then your software fails at runtime (fun fun!) There are a bunch of hadoop bugs where exactly this happened, although I'm too lazy to look up the JIRAs right now.
I feel like if you want a stable version of something, you should use yum, apt-get, or your package manager of choice. I don't think the programming language should try to do the package manager's job. It never seems to end well.
So far, I haven't seen actual harm caused by a lack of library version numbers, and there seems to have been a lot of good done (people using and testing latest versions, green master policy, etc).