Read harder. I didn't say "browsers". I said "serving a page to a client". The world didn't begin with browsers. The web didn't start the internet. The internet wasn't the first network.
In 1994 Bill Gates gave a speech at a computer conference in San Francisco on the concept of a Client Server System.
And he was late to the party with it. MIT had been doing it for 11 years at that point. They had a project that muddied the definitions at the time; the terminal in front of the user was converted to a server and the machines doing the work became the client. The work eventually branched into the X Window System, which anyone who uses Linux knows well.
But even that wasn't the original. Dumb terminals have been around since the beginning. Code trying to make the client into the server has been around since the mid 1970s. The pendulum has been swinging for ages. "Get this stuff off the mainframe and out to the terminals." "Consolidate it back from the terminals and back on the mainframe." "Send this out on the web browser and let the browser do the processing." "Web 2.0 lets us send it all back to the server and get data updates live." "New Responsive pages move the work out to the individual freeing up the servers."
Like the people above, it's a pendulum that we've watched swing back and forth, over and over, for decades. They come with similar problems that we've seen time and time again.