If I was GM id dedicate a huge portion of the salary cap to the lines. Id never draft a corner, safety, rb, LB, or TE in the first round until my Oline and Dline were set. A great Oline makes an average QB better by giving him more time, it makes an avg RB better by giving him wider lanes, and it makes receivers better bc they have that much more time to get open.
A great DL makes the entire defense better for the exact opposite of what was stated above. The best corner in the world cant cover even an avg wide receiver if the QB has 5-6 seconds to throw the ball. Great Linebackers are useless when there are gaping holes at the LOS and they have to make tackles 8yds down field.
Its a simple saying but it really does start at the LOS. Yes, you need talented skill players to make plays, too, but man the overall talent of the team increases exponentially when the o-line and d-lines are dominant.
Unfortunately, i think a lot of GM’s are caught in that trap of wanting to sign or draft the exciting skill players that bring speed and size and generate buzz in the media. It’s harder to get excited about overweight linemen that are slow and look like they just ate a small calf. Everyone wants to drive a Ferrari around; but its the Honda Accord or Toyota Camry that will ultimately get you where you need to go everyday for years.
Id retain proven good/great o-linemen and d-linemen at all costs.