Tend to agree with this. Some may come into a more friendly situation like Darnold, Mahomes and to an extent Jimmy G but all have to perform to make the grade regardless of talent around them. Iron sharpens iron! Elway, Kelly, Aikman, Manning all had to tough it out during an era when QBs weren't coddled.
Some like Alex Smith and Cousins can take years to develop before they become franchise type material.