I think arguing over the label 'fly' vs 'lure' misses the point.
For me there is just as much beauty in an antique bass plug hand crafted form feathers and balsa wood as there is in any salmon fly.
Where I draw the line is in 'machine made mass produced' vs 'hand crafted'. Hand crafted lures and flies come from an age old tradition where folks had to make our own gear. In the old days the skill of a an angler extended to the craft of building, it was hands on. Or at least it expressed the skill of a dedicated craftmen that made these things for sale to others. Flies, lures and rods could be identified on site by the individual skills of the maker.
The modern mass produced market lets anyone with a few bucks and a free weekend call themselves an angler. One rod, mass produced fly or cast plastic lure is indistinguishable from another.
I think some of the aesthetic is lost. I derive a lot of pleasure building rods and tying flies, almost as much as I do fishing with them.