Will, its a thing I’ve pondered over and designed in theory many concepts in ladder stabilization and have discovered there is nothing that can do it better than common sense.
A few sand bags at the base and a tying eye used well is pretty much the best other than a second person footing the ladder.
A general rule of 3 contact points is, I’d think a better way to ensure less ladder accidents.
If anything though, an inbuilt level to ensure best angle of ladder use and adjustable feet.
Wrong angle and unstable ladders are a bigger cause of falls I’d think than the base kicking out.
Some people will always choose to not have a second man and as one design could I think, not suit all working conditions, it would always ve limited.
I’ll do your questionarie later when I’m on a pc.
Like your thought, I just think Darwin needs to do its thing and educate…