I think there are two requirements here: 1) redundancy of work in progress and 2) change control management. I want my work in progress to be relatively safe from failures, I want it to be automatic and I want to be able to choose which changes are worthy of their own revision number in version control. Personally, when committing work in progress I want my revisions to represent a logical stopping point and not necessarily dictated by how much time has elapsed since the last commit.
That way if you go down you can just swap the drive out and be on your way again.
This is what we do (and we have a lot of hard drive churn due to heavy use) and it works well.
For Linux / Windows folks, SuperMicro has a nice tower that has 4 hot swap hard drive bays that I really like.
Speaking only for myself... I have a gold disk plus a little script that syncs scripts and configs to backups. And I use Chrome logged into my Google account.
I do see your point, but a lot of it can be mitigated.