I’ve thought about what I would do if this ever happened due to the fact that SmartThings has absolutely NO customer support with the issue of failed equipment which includes connected devices as well as the Hub.
My thoughts would be to use the wonderful Edge Virtual Device drivers (@TAustin@ygerlovin). My ideas would be that once I got the new Hub online, that I would create virtual devices for everything I have matching the device type. Then mirror everything from Screens to Automations using the virtual devices. Then when I have everything duplicated on the new Hub, start removing the devices from the old hub and connecting them to the new Hub and setting them up using their virtual device counterpart as the guide. Once everything is done, then remove the virtual devices. The only thing that could get in the way is the SmartThings device and Automation trigger limitations, but the jury is still out on if Edge devices limits might be able to exceed the limits of DTH devices.