I'm not sure that skipping SPARC is a bad thing. Who even has SPARC machines sitting around to validate builds? Even Fujitsu moved to ARM for their later cores.
i got a debian maintainer for old IBM mainframes asking me to fix bugs and run tests for that architecture. ¯\_(ツ)_/¯ these people exist, but i'm not going to support them. feel free to fork me!
people who are specially interested in packaging and therefore do it for free care about SPARC.