To further expand on Doug's comments.

I have never been to Banks Island in the Hecate Strait but have visited Haiad Gwhaii (formerly known as the Queen Charlotte Islands) across the strait.

Banks Island is in a northern rainforest environment where annual rainfall is measured in feet and where humdity is usually very high. Lighting an emergency fire there and maintaining that fire for days at this time of year can be challenge for almost any experienced person regardless of method used. Especially where daily rainfall can be upwards of 8 inches or more. The ground and terrain is characterized by very large old and and second growth Cedar, Pine, Fir and other softwood tree species that with their thick canopies block all but the sunniest days of light. In many places, the ground is covered with water saturated downed trees covered in moss and where the thick and almost impenetrable underbrush can make overland travel, all but impossible.

As for luck, yes they had some of that, however for being stranded in such an environment, those fishermen did quite well and were very resourceful with what they found on the island. Making shoes out of styrofoam, how many would think of that?