Actually Kevin, my experience has been just the opposite.
I've seen many more canvas ferrules cracked/broken than I have linen.
Since the canvas is flat laminated, the crack is always along one of the thread lines.
Linen is rolled onto itself (think watch-spring) layer after layer after layer with no set pattern in any of the layers of the weave. There are no potential 'fault-lines' from the interior of the ferrule to the outside.
In any case, I'm sure both versions can be broken if one tries hard enough.