You should check out some of the newer versions of Octave. The graphics in versions 3.0 and 3.2 are very much improved. (Disclosure: I was an active Octave developer a couple of years ago.)

My best experience in managing a moderate sized company was ~400 users where 80-90% of them had thin terminals and only needed about 10 apps. The terminal cost ~$300 each and the maintenance on the terminal was almost nil. If one wasn't working, a local "expert user" put it into a "broken" box and we would take it, reflash it, and if it still didn't work it was replaced. ~2%/yr broke (one every other month).

In my experience, it's a function of how well you're doing your job and how locked down you can make the users' systems. If you do your job well and can effectively totally lock down the system (users install nothing, use Citrix, etc, and are only allowed to use a limited number of apps), that can be perfectly reasonable.

But, the design delays when you would have to buy more disk space. The problem you're referring to is a problem to a specific disk usage scenario. Not all problems are the same, and if you're planning to mass-edit identical files that are a) large enough to make a meaningful impact on your disk usage and b) being edited in a non-uniform way, then don't use the de-duplication feature or plan ahead.