'Unacceptable': Massive BC Ferries lineups to get to Vancouver Island for the long weekend
(vancouverisland.ctvnews.ca)
Some quick googling and it seems the crossing length to the island is similar to the crossing of the English Channel (40 - 50km). The Channel tunnel depth is about 115m below sea level, whereas the Straight of Georgia has an average depth of 150m per Wikipedia. The Channel tunnel cost about 21 billion pounds ($36billion CAD in 2021 dollars) to complete, so I'd imagine a tunnel to Vancouver Island would be at least the same if not more. Doesn't seem worth it for the size of the population crossing even if it were possible.