Downgrading to macOS Catalina: A Sermon on Obsolescence

There's a MacBook Pro sitting on my desk that is, by any reasonable measure, a good computer. It runs code. Browses the web. Opens documents, plays music, handles a terminal. The CPU still computes. Keyboard works. "Retina" screen has no dead pixels. ...Okay, it does always need to be plugged in because the 3rd party battery mysteriously died after only a couple hundred cycles. But by the standards of most of human history, this object is a miracle! A slab of aluminum and glass containing more computational power than the entire Apollo program, purchased used on Kijiji for a few hundred dollars, doing what I need it to do. Apple disagrees. This is going to be a technical tutorial, but it is also a look into how companies stop updating your machine, stop optimizing their software for it, and then keep shipping new releases designed for hardware you don't own. The machine becomes less capable than it was. Gradually, imperceptibly, deliberately Slower. Hotter. More stubborn. It's been dec