Re "nobody else made an alternative", nobody wanted it in the first place except Pootering. There already was an init. Who wants a boot that is different each time and after ten years of dev still cant shutdown. What you want in a server is a reliable reboot. Speed does not matter when you have redundancy of servers. Systemd is fine, as an option, for laptops. The alternative was stable. Still is.
I rarely reboot my laptop. Care not about the speed. Be nice if it would reboot eventually when I type init 6 tho.