Right now, Wilson is scoring 1 TD per game in every game but 1 this year.
There are about 15 other QBs that can do better than that in the league now, even with this line.
What we did do is pay someone big money that is going to starve the rest of the team (like what happened to the Ravens with Flacco), assuring we won't be getting better but probably will be getting worse.
20M per year QBs need to score more than 1 TD per game. Wilson is terrible at converting possessions in scoring territory into TDs this year and that is a key reason we are struggling.
But since there isn't a big giant free agent market in competent QBs, we are pretty much stuck overpaying for the results we are getting. (note: we are not really paying him $20M this year in terms of cap hit, so this only matters if he is playing like this next year).