I have both opinions: certain canvas bags will last you a lifetime and even you can fix them if necessary.
Most stores sell you "bags for life" that aren't either recyclable (truly) nor meant to last a year of daily usage, probably because they are cheaping out on the materials and production.
So we still end with a pile of garbage.
However, I am against single-use anything and would say that promoting truly lasting bags should be a priority over trying to figure out a solution for a single facet of a large issue.