It’s only the last 5 years, give or take, that you can install C-compiled packages with pip. When I started out, I had to apt/port/pacman install packages, then run pip install (or python setup.py even) to install dependencies. It’s hard for newer python converts to even comprehend the pain it used to be. Conda came with the compiled package concept, and pip came after. Dealing with dependencies these days is a breeze, relatively speaking. On windows you even needed a visual studio license, just to pip install numpy!
Just because the egg/wheel format existed, didn't mean that they where actually used and actually worked. Being able to reliable pip install packages like numpy and gdal only started 3-4 years ago. There is a reason that Christoph Gohlke's python package site exists and was popular.
I started using numpy around 2007 and didn’t see reliable binary installs with good numerical performance until I discovered anaconda, much later (2016?). Maybe I hung out with the wrong people, or libraries. Some libraries did not have compiled wheels a few years ago, and M1 macs still run into the very occasional issue.
You’re running install-time code if you don’t, so I disagree. The wheel format is better suited even for pure python distribution. You can read more details on that site.
