I have my updates set to “download only” to avoid any potential issues like this. There aren’t many updates that are so important that they require immediate application. When I have a spare ten minutes, and I’m not using my phone, I install the already downloaded update.

As far as a lawsuit for material loss, your loss was avoidable by adjusting your settings. I’m sure there’s lawyers out there that will pick it up as a class action..they love those. But unless apple settles, it wont be difficult proving the user shares some responsibility.