It's also an injured Amendola who is basically a roster spot right now. It's pretty obvious from watching him he's about 50% right now and has no burst. Plus, it's the cumulative impact of everything. No Edelman and ineffective Amendola means no guys who can get open fast. No guys who can get open fast means you have to hold onto the ball. Decimated by injuries up front compound the issue. No Vollmer impacts the guards, impacted guards impacts the center. Needing to keep additional protection in nullifies backs and tight end.
The cumulative impact on the key players returning to the lineup is equally impactful in a positive direction. Opens other receivers up, gives the offense more ability to mask line issues, continuity in the line helps pickup, etc, etc...
Football can't be viewed in the vacuum of single player impact. Same goes with the defense. The whole is always going to be greater than the sum of its parts. This team, if healthy, is going to be incredibly difficult to beat and should be expected to beat anyone they will face moving forward. These past games can't be taken as representations of how the actual team will look. They're wearing Patriots jerseys but they're not the team they will be fielding in two weeks.