The reason we used tables was because getting things right in CSS in the early days across all of the browsers was a nightmare. An expensive nightmare. Which was fine if you were a well funded startup and could afford to rebuild your HTML regularly.
CSS at the time was still a leaky abstraction: in order to get things working, you had to include extraneous DIVs in the HTML code as anchors for the CSS rules.
The standard body has attempted to address this issue with pseudo-elements and pseudo-classes as well as other features I may not be aware of.
At least though, these extra DIVs weren't disrupting the page layout (eg. when disabling the CSS - something that was still possible at the time), which was beneficial for accessibility.
I kept our internal reporting site running for 3-4 years, I used CSS for layout.. it required regular maintenance but I had enough time to do it as my main job was as a Database Admin / Data Engineer (I'd have been called "devops engineer" nowadays as I had quite a broad set of responsibilities).
It always felt like a fun challenge. For me, it was a crucial part of my love of the web (and eventually, programming): the hackability and the way that there was no canonical correct way to solve a given problem. I miss those days.
