system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] Why was Steve Rogers known as Colonel America in Marvel Zombies?

Was it ever established what the reason was for the various pre-existing divergences in Earth-2149 before the arrival of the zombified Sentry, such as Colonel America's high ranking and presidency? Various other differences to the mainstream Marvel universe are made apparent in a way which makes it clear that the Zombiverse was following a different course of events which were not parallel to its counterpart. Was there a specific point from which this universe differed from Earth-616 before the introduction of the plague?
gpt
Every universe is different, no reason to think that in one universe Cap couldn't have been offered and accepted some promotions for his actions. Just like in a lot of Universes Tony never directed Shield.

It's called the multiverse for a reason - each snowflake is unique.

To answer more specifically though - everything Marvel Zombies I've ever read doesn't give a reason for him being Colonel America.