I'm going to say "Motorcycles". (At least bikes in the US.)

20 years ago, a lot of bikes still had carburetors with manual choke. Many of them had no pollution controls at all. ABS was basically science fiction. A significant portion of them were air cooled. (To be clear, there are still some air cooled bikes on the market.)

Now it's rare to find carbs on street legal bikes, even the 125cc Grom has fuel injection. And basically any bike has at least a catalytic converter. There are bikes with variable valve timing. There are bikes made by Harley-Davidson (The company always the butt of "muh primitive motorcycle" jokes) that have water cooled engines with variable valve timing that make as much noise, and vibration, as the average Toyota. Most bikes have ABS on them now, and there are plenty with traction control and stability control. They're safer now than they used to be. I recently sold a couple of bikes and bought one nicer bike, and it's uncanny how smooth, quiet, and stable it is.