AMD only added KMS to their proprietary driver last year, and Nvidia this year (and IIRC only in a beta driver so far); and systemd makes the permission handling a lot easier. So Ubuntu will transition to it eventually, but didn't have all puzzle pieces until too recently for even 16.04 LTS.
AMD only added KMS to their proprietary driver last year, and Nvidia this year (and IIRC only in a beta driver so far); and systemd makes the permission handling a lot easier. So Ubuntu will transition to it eventually, but didn't have all puzzle pieces until too recently for even 16.04 LTS.