Where did you get me saying Sanchez wasn't good from?
This:
I will never not be convinced that both Rex and Sanchez wouldn't have had very different career arcs if that hadn't happened.
Working past your double negative, you seem to be saying that Rex and Sanchez would have had the same basic careers (or "not different") had their paths not crossed or Sanchez not gotten injured. Sanchez never again became a starter in a league loaded with teams who desperately needed one, which indicates he was never that good. Somehow we won four road playoff games with him as a rookie and a second year player.
I have always been a Sanchez apologist. I believe we fucked him up in a number of ways, but if Rex hadn't put Sanchez back out there to get injured against the Giants, both of them would have lasted much longer in New York. They both had a lot of goodwill from the fanbase still which was well earned from the playoff runs, and another season of development from Sanchez could have seen them both back on an upward trajectory. The lost season for Sanchez was where excrement really fell apart for them both.
Here you seem to be saying the opposite. It's possible, it would have depended on how Sanchez did that year as opposed to Geno as a rookie. I think Sanchez benefited from Rex having a good D and keeping us in games; conversely I think a better, more experienced QB at any time in Rex's tenure here would have made a big difference. Belichick was a defensive specialist with a losing record as a head coach until Brady went in. If we had Favre or a healthy Pennington to handle the offense we'd have been much better off.
For the record I was also a huge Sanchez apologist in his time here and was kind of surprised he never managed to start for the rest of his career on teams like Denver and the Bears. Dak beat him out as a rookie but he turned out to be a very good QB.