You are insisting on justifying all of the complexity of browsers by claiming the same functionality that people got in the 70's with a small OS that was hand-written in assembly.
Sorry, but you don't seem to want a productive discussion. You just have a preconceived idea that turns out to be wrong.
I am not insisting anything. I wanted to point out that the "reason why browsers exist/came to exist" can be relevant in this discussion but is not a direct logical contradiction to their current complexity.
If I say, the pdf came to be in order to be a simple way to digitally represent printed/printable documents that may be correct but wouldn't actually express anything about the current complexity of the pdf format. Admittedly perhaps a bad example due to how similar it is.
It's possible I misunderstood though. If so, I apologize.
Sorry, but you don't seem to want a productive discussion. You just have a preconceived idea that turns out to be wrong.