Nick, before being rough please read my answer again.
The drink bottle allows someone to physically grasp the concept of stiffness and hinge offset. Which as you point out is something that isn't often addressed in casual discussions.
Reducing the hinge offset to zero is the next step whereby you have to imagine the thrust vector in terms vertical and lateral. The second part of my answer, replacing the strings with a straw, therefore gives an appreciation of the interaction of the cg with an offset force.
I've always found the two taken together to be a good hands on introduction to help someone understand these fundamental points. Of course you are entitled to hold a different opinion.
On a personal note I'm glad that you are well and posting.