Yes, but as usual here, all fiberglass covered canoes are being lumped into the same category - as if they all share the same properties and/or liabilities. The fact that you can find a fiberglass canoe which was obviously and seriously abused and is now trashed because of it doesn't show anything other than the fact that it was owned by an idiot. I firmly believe that during the late 1960s and 1970s there were people at Old Town and some other companies who saw glass covering as the way of the future - something that would become the standard, along with avocado-colored refrigerators and stoves. Unfortunately, the resin technology wasn't advanced enough at that time for it to really happen.
The fiberglassed Old Towns were glassed using polyester resin, which doesn't really stick to or seal wood all that well. This is also why boat graveyards are full of old fiberglass powerboats with rotting sheets of fiberglassed plywood in their transoms. There isn't a single polyester resin formula that has been made with using it on wood in mind. Yes MGC, Trappers (glass covered) Lightweights (canvas) and Featherweights (Dacron) used thinner planking. Others which could be special ordered fiberglassed (Old Town called it "reinforced plastic" covering) still had their normal plank thickness to the best of my knowledge. For those of us who were retailers, one thing about the issue is that the clear finished Trappers always sold at least twice as quickly as any canoe with a painted hull, whether fiberglassed, canvased or whatever. You just hoped the new owners would baby it, because hitting rocks was likely to cause delaminations, which would be very obviously visible.
I'm all for folks doing their own work on their boats when they can, but when it comes to glassing a canoe, there is a very small percentage of them who have the skills, knowledge and experience to do it well, and anything less is likely to have problems down the road. I think the odds of them managing to do a reasonably nice job with canvas are much higher, and even if it isn't perfect, it can always be fairly easily replaced. On the other hand, canvas certainly does not, and will not, prevent serious deterioration and the eventual destruction of the canoe if it is not given reasonable care. That is by no means something which only happens to fiberglass covered canoes, and I doubt the time line for it to happen will be much different.