I can't abide by any single dogmatic rule... As always in all things canoeing the correct answer is Maybe.
I've gotta agree with YC here... It all depends on the purpose of the trip.
I went through an "ultralight backpacking" phase about 2001/2-ish. I was in my late 30s, back was starting to give out, I was still in somewhat good physical condition (lived near the Smokies and dayhiked a lot, and had gotten out of the military just a few years before). But I felt I was working too hard. So, in due time, I got my "base weight" (from skin out, minus food, water, and fuel, since they vary by the number of days out) down to about 12 lbs... add back food at 2lbs per day, 2 qts of water (4lbs), and some fuel, and I could do a 3-day weekend on under 25lbs.
At some point, I took my daughter canoeing locally, and eventually built a stitch and glue canoe with her, in 2007, I think... Then, in 2008, I took her to the Adirondacks, on the Bog River, on her first multi-day camping trip... since I was carrying almost everything, and doing most of the work in paddling, and she was pretty young (and small), I kept it as light as possible... This was good, in that it taught her to pack light (which she still does, mostly).
But I realized just how much I could have carried easily, and over the years, I've relaxed a bit and my 'base weight' has crept back up into the teens. I now carry a Magellan air pillow, a larger hammock tarp, quite frequently (even solo) a HUGE 14x20 cooking tarp, more food/snacks, sometimes a small dutch oven, saw/hatchet, and a few other odds and ends.
Not a huge load, as I still prefer to single carry on portages. But I tailor it to the trip now... for the St Regis route into Fish Pond, I'll rent a PBW RapidFire and go back to being ultralight again... for that same trip, but only doing Hoel, Slang, Turtle, and Long, I'll break out the big tarp and the wannagen box. For Low's/Bog River, it's about the same... one simple, short portage. For many of my local waterways, I can load up with chairs, dutch oven, etc...
So, bottom line, it depends on the trip... the only constant is that as I'm getting older, I try to do less and less work on said trips.