Have you literally not heard of WiFi repeaters? It is a whole device category.

You can say that to just about anything. Every weapon system uses stuff that was not developed for this use case. Because so many things are involved there.

To be honest, using an actual threadmill has no actual benefits other than generating an interesting headline

In the picture is no tube going to the toolhead. The white line you see is the filament. The Bowden tube is only connected to the frame. That means that every time the toolhead moves to either side, it will tug on the filament. potentially creating artifacts in the print and maybe even causing underextrusion and slipping extruder gears.

Yes, that will cause problems. Don’t attach it to the frame. Attach it directly to the toolhead.