A few corrections to this.
Not “all” modern cars have this but it’s pretty common. But, when people say “variable ratio” there are really two different systems. There is this one and then there is a fully variable system. That one actually uses a device to literally change the ratio based on parameters such as speed, etc. It doesn’t consist of a rack with variable spaced teeth, it consists of a set of gears which can instantly change the angle of steering vs. angle of wheel input at any time. It’s been around for a number of years. Audi and BMW use it.
some say it’s odd feeling, others don’t mind.
www.audi-technology-portal.de