The Pats lost to three teams with a combined record of 10-2, all of which are in the top five or six of the power rankings of the league, and the Pats were competitive in, and reasonably a few plays away from winning, two of those games. (Maybe that's a stretch in the Dolphins game, but I think it's absolutely true of the Eagles game.)
It doesn't look great right now, but maybe give Belichick and this team a few more games before considering them both lost causes?
They played the 4-0 Eagles evenly. They lost a close game to the 3-1 Dolphins. They beat the Jets - a team that beat Buffalo and got lost a close game to the defending SB champs. Then, yeah, they got absolutely mauled by the Cowboys.
Here are some other teams that have gotten destroyed this year:
Cin - 24-3 to the Browns and 27-3 to the Titans
Pit - 30-7 to the 49ers and 30-6 to the Texans
Sea - 30-13 to the Rams
NYG - 40-0 to the Cowboys and 30-12 to the 49ers
LV - 38-10 to the Bills
NYJ - 30-10 to the Cowboys
Ten - 30-12 to the Browns
Den - 70-20 to the Dolphins
Was - 37-3 to the Bills
Jax - 37-17 to the Texans
Chi - 41-10 to the Chiefs
Mia - 48-20 to the Bills
Cle - 28-3 to the Ravens
NO - 26-9 to the Bucs
Ari - 35-16 to the 49ers
So that's 15 teams in the NFL that have suffered absolutely demolitions at the hands of their oppositions - three of them have had it happen twice. And of those teams that have suffered humongous defeats, the following either made the playoffs last year or who were widely considered to be legit playoff contenders this year:
Cincinnati
Pittsburgh
Seattle
NY Giants
NY Jets (granted, this was with Rodgers at QB)
Jacksonville
Miami
New Orleans
So yeah, getting bludgeoned by Dallas sucks, but (a) Dallas has done this to three teams already this year, and (b) lots of other erstwhile "good" teams have gotten their asses handed to them at least once already this year, so NE has plenty of company.