One could say that in most cases it was a matter of the hunter "not doing his part". Whether it is in bullet choice, rifle choice, calibre choice, lack of practice, etc. It really takes very little to kill a 100# WV WT if a precise shot is made at a calm deer. If the same deer has his blood up and is already fleeing, they can absorb an amazing amount of punishment.
One of the grains of partial truth your myths is the magnum shooters that bought into the "kinetic energy" BS. They would take a light for calibre bullet and drive it at warp speed. (it really impresses the non shooters around the water cooler at work) The bullets of the day would be coming apart before they hit the animal and so, when it did, it would shatter, causing extensive meat damage or a grievous wound and the animal would escape. It, of course, couldn't be the hunter's fault for not knowing what he was doing so it had to be a bullet failure. Don'tchaknow.
So now, they are making the bonded, boutique bullets and the fellows shooting standard calibre rifles are buying them when they would be better off with the old fashioned cup and core bullets.
And, of course, you have the type that want to appear as some sort of Cool Hand Luke that never makes a shot that isn't exactly perfect. You wonder if he has actually ever been hunting. So when some pilgrim wonders in and sez, "I'm spending $10,000 on a guided elk hunt, can I use my .243 with 75gr target bullets?" He pops up and sez "oh hell yes, it's all I ever use and my Grandpa has been using the same load since he was a boy." And a chorus of other wannabes chime in with "yeah, me too".
But remember, if this hadn't started out as a thinly disguised "let's bash the guys that shoot real guns" thread, we wouldn't be having this conversation.