MainSail paid $700/yr in 2008 for a boat in a similar size range to my sailboat. Allowing for inflation, my 1996 canvas cover (including the frame) would have cost $4400 in 2008 dollars. I've had it for 16 years without a collapse--although I'm admittedly not in Maine! Shrink wrap would have cost me over $11K in that time frame if done like MainSail's.
Having a steep enough slope is a key here, as well as some way to offload the lifelines. My frame has arches at close intervals and a stringer halfway from the ridgepole to the lifelines. The ridgepole is supported vertically at close intervals. In a heavy snow load, there is enough sagging that the lifelines will take some of the load, but the stanchions are backed up by the arches. This works in SE Connecticut, where we get wet snows often enough. Not saying this slope or the frame design is suitable for Maine.
I have seen the downside of shrinkwrap on painted hulls in my yard, so canvas makes a lot of sense if you like a bubble-free hull.