After manually installing the .NET Framework 4.6 & re-booting, then running the /createMsi, the command succeeded as expected.
This leads to next issues: The now required .NET Framework 4.6 is however now causing issues with silent installation I'm doing with the .msi's. The installation turns out as failed if the computer doesn't already have .NET Framework 4.6 installed. When running the .msi manually (attended), the installer fails with an error "There is a problem with this Windows Installer package. A program run as part of the setup did not finish as expected. Contact your suppor