There is luck involved, but teams/players/coaches can make their own luck be it good or bad also.
Some of what is refered to as luck, is just a player making a great play, and a team properly motivated and not giving up.
Also playing smart.
The Dez play had many stupid elements to it. I dont see that as bad luck
The helmet catch was just a great play.
Clark in endzone, great play by him, montana, and SF team. There was still a factor of good luck, but without the great play and effort that luck means
nothing.