Does anyone else arrange their data in a way that protects against the inevitability of a windows install failing??
No...I arrange it against the potential of the OS install failing. No OS is infallible or immune to you or some bad other thing happening. I wouldn't put my data on the same partition of a Linux install either- I wouldn't put it on the same disk even, if I could avoid it, just like on Windows. If for no other reason than historically, having all your stuff on the same disk as the OS could cause really significant performance impacts. It's less of an issue with solid state storage, but it's still there, to say nothing of storage density of hard disks vs solid state.
Plus, depending on what you are doing, it's very possible that your OS disk is the most active one in your system, so it's going to potentially have wear related problems much sooner than your data disks.