Universal Easy Installer
This might be something that may have been considered.
To encourage even non-tech users the move to Ubunto, one of the main factors - simplicity of getting onto it, shouldn't be overlooked.
Why not make a tool that will do everything for the user, from automatically extracting drivers of all the hardware (and other necessary functional items) on the existing Android OS to automatically compiling the extractions/conversions with the latest releases of Ubunto and automatically flashing all in a few clicks.
Is this achievable?
Hmm did you ever try https://github.com/ubports/ubports-installer/releases ? Its nearly what you describe, yet we cannot automate all the steps. For example, setting the phone to developer mode needs to be done manually. Unlocking the boot loader will wipe Android and all data, so we also cannot do this automatically, otherwise people will hate us.
Everything else is done by the installer already.
@rossrosh: Like Flohack said, the UBPorts installer exists and works great, see here: https://forums.ubports.com/topic/976/ubports-installer-excellent-user-experience