Also in many cinemas there are special "pads" that are attached to the frame of your glasses, hold on the bridge of the nose, do not interfere, and do not force you to sit in two glasses.
As far as I know, they are usually there available, simply ask for them.
I personally watch 3D films wearing 3D glasses over my usual glasses, exactly as shown in your illustration to the question, and I don't feel any discomfort at all. Therefore, based on my experience, I will assume that they do not come up with anything because most of the bespectacled people also have no problems with this.
You don't need to invent anything, the cinema just needs to buy additional glasses that can be worn on glasses with diopters. There are such, nothing complicated. It's just that cinemas are fine. Many people already wear glasses over glasses, or come in contact lenses. Until competition forces itself to position itself as a glasses-friendly cinema, nothing will change. And, as I understand it, cinemas with 3D are not idle yet, so discrimination ...