A traditional monitor is 16:9: that means for every unit of height, there is 1.77 units of height.
It sounds like a small difference, but it means a ~15% increase in height.
ex. my Visual Studio Code would show 70 lines of code instead of 60.
This is an especially good tradeoff for code, because we tradtional line wrap at ~80 characters, which leaves large swaths of width available.
They were, but I recall 4:3 monitors lacking the width to comfortably accommodate things like IDE project views AND code simultaneously.
I believe 16:10 was chose as a nice aspect ratio for productivity, but 16:9 was chosen for movies/TV, and economies of scale and cost reduction impulses meant they took over even in areas where they were a stupidly poor choice (observe all the laptops with massively fat bezels [1]).
[1] For example: https://www.pcgamer.com/asus-new-rog-strix-laptops-deliver-a..., https://www.amazon.com/GIGABYTE-AORUS-1920x1080-i5-12500H-9M...
First 16:9 was probably 2006...got the first ever MacBook Pro as my graduation gift
It informed some conception I had of the iPad as a platonic ideal (first 4:3 monitor in years)
The wideness of 16:9 means those monitors have too little vertical real-estate.
