I'm not sure what you mean. Romulus was worshipped. Both as a sort of local Genius and in association with Quirinus. Romulus was a god, and was owed divine offerings and honors. The supposed Hut of Romulus was a cult site, he was associated with the Lupercal and the pomerium, etc. Mind you, just because his story seems overtly religious does not mean it predates his cult or vice versa. The Romulus version of the foundation story clearly borrows from Greek and Italian antecedents, and its actual antiquity is unclear.

Are you asking why Romulus didn't become Christ? That's somewhat misunderstanding the way ancient religion worked, and how these stories came to be. If I'm not mistaken it's also misunderstanding how the stories of Christ came to be--the miracles of the New Testament, last time I checked, are thought by scholars to have been established as stories only after the Christians as a group became established. I'm not really sure I understand what you're getting at