No tackle on the d-line would be a starter on any other NFL team. Not one. Most would be a "we hope we only need him for a game or two" backups.
Though even with a top DT, would it really help? On Jackson's 37 yard td run (if memory serves) LVE was right in front of where Jackson ran. But before Jackson got to the line, LVE went to his right and left the entire middle of the line wide open. There was no safety in the middle. That is coaching, scheme and technique. LVE is perfectly capable of standing in the middle of the line and at least slowing down Jackson, and if a safety is there he can at least make Jackson make some moves instead of making a bee line for the end zone. For goodness' sake, these near 66 year old legs could have scored on that play, or at least gotten close to the end zone.
The players aren't without fault, but it's coaching AND players that are underperforming, and that combination (sounds like one of those diet commercials saying eating certain foods in COMBINATION will make you lose lots of weight) gives you the worst defense in the NFC (or NFL maybe)....