The canvas is also lighter weight than leather. Everytime I pick up one of my bags at is all leather, I get shocked its weight.
Absolutely - I don't have an LV bag but I have a coated canvas LAMB and my shoulder pain that I had for years went away after just a few days of not carrying a leather bag (and mine weren't particularly heavy either).
Leather doesn't mean expensive - I've had many leather bags that cost $50 or less. What makes a bag worth its cost or not is the overall quality and amount of work involved, not the basic material.
I know a few vegetarians who like LV because they use 'less' leather (just for trim) rather than 'fake' leather (pleather) that still looks like a leather bag.