I decided to look into the full numbers behind it.
The Canucks have been in a 3-1 series a total of 19 times in their history. Of those, 8 ended in game 5, 4 ended in game 6 and 7 ended in game 7.
When you narrow that down to the Canucks being the team down 3-1, only 3 times did they lose game 5, twice they lost game 6 and they went 3-1 in game 7s for a total record of 3 series wins and 6 losses. A 33% chance to win the series isn't really any worse than most people's odds on the Canucks before the series started.