I didn't say they need to win the SB this season or McD is out (no need to keep repeating that). But he has to get this stacked team to the SB this year (his 6th) or it can be legitimately questioned whether he ever will. "Teambuilding" is one thing. Coaching in the big games is another matter altogether...
Paxton, Cartright and Horace Grant are not quite a stacked roster lol. The Bills are.
Dungy (perhaps the most overrate NFL HC of all time) didn't build much of a team: the Defense was consistently excellent. The Offenses were mediocre or awful. Gruden took that 9-7 and won a SB. After that, the team "fell apart" because his QBs were Griese (not Bob), Simms (not Phil), Bruce Gradkowski, and Jeff Garcia.
McD has to bring them past KC and to the SB. He has all the talent he's going to get, and it is sufficient for the task.