The strength of the culture he has installed in LA specifically. From day one they got the most from that roster that they could. This wasn't a star studded roster in 2017. We had a star RB in Gurley and a star DT in Donald and a bunch of guys. We had a QB who needed a clean pocket and Gurley's plus rush threat to be effective. And in the playoffs that year of course the roster wilted in the heat of competition.
But either way McVay's effect was seen day one. And it's his effect that allows for bringing in all these veterans with all that talent and getting them all in line and producing. Replace him with a lesser head coach and you'd see the entire thing quickly disintegrate. His grasp of culture and getting everyone on one page is a crucial element in this draft strategy.
The very moment a paid veteran gets the feeling the team doesn't have a chance he is immediately going to start cruising and being careful and not playing balls to the wall like they just did during that championship run. So you can want to pursue this strategy as a GM. But if you don't have the right coach good luck with that. Snead wasn't anything special with Fisher at the helm. Install McVay though and all of a sudden his instincts can supplement a rare coach and help us sustain something special.