KHTML+KJS released in 1998, via WebKit from 2001, in 2008 it gained the Chrome name, but the code has more than 20 years of legacy.
...ok the /bin /usr/bin nonsense still stays after decades, maybe you have a point
Why do you want the oldest code to be less than 20 years old? Why is that "nice"?
The major browser platform today, smartphones, did not exist. PDAs did not even have wireless internet yet.
The basis for the functionality of the browser is due for a reimagining.