Why aren't cloud, or even local, VM's being brought up? You irrevocably blow up your linux VM... just spin up a new one - or revert to your snapshot from earlier in the day. I'd actually make the argument that virtualization would make it easier than ever to safely experiment with things. Complexity has definitely gone up, and the time and ability to peacefully munch on problems under a tree has definitely gone down. But, I would argue that if a learner given the right sort of virtual sandbox, instructions on how to reset their state to working order, and an internet connection with google, the linux docs, and stack overflow bookmarked, there is a lot of learning to be had!