So the only thing I'm trying hard enough to do is see how anyone can't tell the difference between the strength of wood versus cotton & nylon.
Perhaps you undersestimate the tensile strength and/or elastic modulus of rigid thermoplastics?
Irrespective of that sort of data, here's three experiments. You can do these as thought experiments, or, if you have access to a typical Fender-style tolex/plywood rectangular HSC and a modern hybrid bag, like a Mono M80 or Protec Contego, perhaps you'd be willing to load them both up with your basses, perform these tests, and let us know how they came out?
#1 - paint the inside lid (the inside top cover) off the HSC and the hybrid bag with a thick coat of oil-based paint. While the paint is still wet, put your bass inside, and close the lid. How much weight on top of the case/bag would it require before wet paint got on your bass?
#2 - set the stops on an industrial drill press to 3/8". Lay the HSC (loaded with your bass) horizontally on the work table and drill a hole or ten dead center. Repeat with the hybrid bag. Which bass survived unscathed?
#3 - remove the basses from both cases, replace them with a large fresh ostritch egg. Drop cases onto a concrete floor from various heights, starting at ~3' and going up to, oh, say, ~10'. Which case required you to deploy the industrial-strength fabric cleaner sooner?
It is my contention that a modern hybrid gig bag
far surpasses a traditional rectangular Fender-style plywood/tolex hardshell case in the areas those experiments are designed to test: Top deformation, isolation from less-than-catastrophically-deep punctures, and shock isolation.
I've been fortunate in that I've never gathered any empirical evidence vis a vis punctures, but I have had a couple basses sustain minor damage due to the top deformation of a Fender HSC (one involved gear stacked next to it in the truck, the other involved some idiot stepping on the case while it lay on its back), and I've had three basses suffer minor damage -- and one suffer
major damage, headstock snapped clean off -- due to the lack of shock protection in a Fender-style HSC. And I am really comfortably confident that had any of those instruments been in, say, a Mono M80, none of that damage would have happened.