I would have enjoyed this but didn't understand it. I think the main problem is that I didn't understand what they meant by tyres "being flat" so the rest of it was impossible to grok.
It's not the tires that are flat, it's the face of the rims.
The parts of the suspension the wheel turns on are pushed out towards the center of the contact patch on newer cars to reduce the forces that feed back to the steering wheel. The different steering system used on older cars benefited from those larger forces (because the systems didn't have good feedback).
They're talking about the wheels, not the tyres.