You are overreaching in your criticism. systemd works on Ubuntu and Gentoo just fine. If the distributions don't choose to make it the default, that is certainly a valid choice but Lennart didn't abandon anything in that case. Moreover, if you read the full blog post, Lennart doesn't claim systemd is a standard platform. Quite the contrary, he says he has failed to achieve the standardization he set out as one of the goals of systemd, in part because systemd developers haven't pushed for use of it to manage user sessions yet although it is possible to do so now.