Several ways to answer this:
1) Who else was and is available that is a proven quality starter? How much does he cost and what do better options cost? Is the difference that much?
2) He was the top rated QB in the league when he got hurt. He lost two games to Philly and ATL where he scored in final minute. He’s done a lot more good for this team than bad. He’s a very good fit in this offense with the deep ball play action. Do you remember before he got here and we didn’t have the ability to have a functional 2 minute offense?
3) If you want to tank. There’s an about a 20% chance or less we will hit on a star QB. There’s a lot bigger than that we will plummet into a decade of coaching carousels.