Revisionist history. Peyton Manning was highly, highly, criticized for not winning playoff games early in his career.
Note also that, in year 5, he made the AFCG. What year is Lamar in, currently?
Peyton Manning wasn't in the stratosphere of being considered one of the great QBs in history after his first 3-4 years in the league. He reached that level later in his career, when from 2003-2015, if my math is correct, he won 14 playoff games, made 6 conference championship games, made 4 super bowls, won 2 SBs, and had won five MVPs.