In some parts of the world PCs are quite expensive. In the US you can get a cheap laptop on black Friday which costs as much as a Ledger Blue so I figured it's not that much of a burden financially. I guess it's more a matter of how meticulous people are with their online safety.
What I like to do is use a Raspberry Pi when I need something secure. It's cheap and small. I even use it as my cold storage wallet and though I can't say its as secure as a Ledger, it's a pretty safe way of storing Bitcoins for $35. Anyhow, I think using a USB disk drive as a live CD is a viable and cheap idea as well.