There simply isn't a lot of precedent for what the 2018 Chiefs are trying to do. Not in the current century, anyway.
The Chiefs are preparing — enthusiastically, it should be noted — for the upcoming season with the apparent plan of trying to win games 42-38 with a first-year starting quarterback.
Recent NFL history is full of examples of teams winning with rookie or first-year quarterbacks. Tom Brady is the best example, winning the Super Bowl after the 2001 season, but he did begin that season as the backup. Russell Wilson, Ben Roethlisberger, and Joe Flacco are among other rookie quarterbacks to make the playoffs.