It absolutely is. The fact that “sacks and TFL” are what determine a defensive players worth is very shallow-thinking.
Here is why the 49ers don’t have to worry about a Parsons-level to gameplay around this week. Here is why Parsons got a DPOY nod over Reddick.
I don’t mind Parsons over Reddick vis a vis (I also don’t care about the individual awards but I do think that if Reddick’s name was ‘Micah Parsons,’ he would be a finalist). Reddick is a straight pass rusher while Parsons does get asked to do other things, which includes taking more snaps.
I think your original idea here makes more sense for almost anybody else on the league, apart from a very select few, but your example here would serve to further my point more. Micah Parsons is different. I don’t need to tell you that. Offenses will take virtually any snap that he doesn’t get to the QB, no matter how much he actually beats his matchup, even more so when no one else gets there for him, but it’s still up to them to scheme him to get him there if he can’t do it on his own and other don’t do it enough, and there was a direct correlation to the Cowboys beginning to struggle scheming their defense when other teams figured out that happens when Parsons gets bottled up.
And I don’t doubt that Trent Williams can handle Reddick, but the Eagles pass rush this season is historic. I don’t know off-hand how many times Williams got help, but on average it almost definitely won’t be as many as he gets this week because the Eagles have too many guys who get home. Assuming the 49ers even pass enough, one way to stop the Eagles pass rush would be to simply not pass.