I love Ada, and I've written Ada code, but there are so few people who know it that building a community around an init system built in Ada is very difficult. The barrier of entry for contributions is "learn this language developed by the DoD thirty years ago that you won't use unless you work on embedded systems, in the US, for a living." I agree that it's a better technological choice than C, for any systems-level program, but Red Hat, like virtually any company out there, cares about money more than tech.

FreePascal, Oberon, ActiveOberon, are all great (I'm hesitant to say I know Oberon since I haven't written Oberon code in like 15 years), but besides having the same problem as Ada above, the communities maintaining the compilers are small and understandingly fragile. systemd is still going to be here 15 years from now. Oberon -- who knows?

Modula really belongs in a museum :-).

Besides, they'd all need things like D-Bus bindings etc., a working, stable compiler is just the first step.