This "rule emphasis change" has unintended consequences. There are two ways to stop an NFL passing attack: Don't let receivers get open and get after the passer. Teams like SF, Chicago and Washington have sunk huge resources into acquiring pass rushers; that is the identity of their defenses. If offensive lines are suddenly able hold with near impunity, it neutralizes pass rushers (although it didn't seem to help against Aaron Donald), and makes defensive back play paramount. If this change is permanent, the value of true cover cornerbacks is going to go through the roof and teams who have invested heavily in pass rushers will be left holding the bag.