If you read ancient articles like this one https://support.microsoft.com/en-us/topic/dynamic-page-updat... you can truly see just how much it changed the internet.
We were using that XMLHTTP object as far back as 1999 (I just went to look at old source code) to load page fragments do quasi-SPA stuff before it was a thing.
It was completely unnecessary (at least the look and feel part) but the ability to load in new information into the UI without a full refresh was great.
At the time this was running on Apache 1.1 via Perl CGIs and backed by an mSQL database (that was single-threaded!) so we wanted to minimize complex SQL queries as much as possible..
We eventually moved to a system that would batch pre-render customer details and call history to static HTML overnight when our call center was closed, to reduce the startup time of bringing up a customer's info when the agent had them on the phone. Then for that day we'd use XMLHttp to dynamically append new information from the DB (using a limit statement) and then re-build the static files the next night etc..
In hindsight, we did some creative problem solving for a bunch of self-taught 20-year-olds in the 90s.
For instance, #2 (<table>-based layouts) definitely shaped much of early-to-mid-2000s web design, and can be viewed as a precursor to flexbox/other modern layout engines.
Same with sIFR -- custom webfonts are totally taken for granted today largely because of "hacks" like this.
Same story with rounded corners, which were originally accomplished with tables and images. And a lot of the conventions for website navigation were established in table-based layouts
I guess that would be just called "history of the internet". Originally designed to display text with links - and after decades of hacks, a browser is now allmost an OS, capable of allmost anything computer related.