You have to account for resale when it comes to TCO. Resale value for a non-Apple PC is essentially zero - i.e. no one will buy it, or you'll get pennies on the dollar if they do. Whereas there's a strong market for used Apple hardware, and you can easily recover 50% or more.
Do people actually buy used computers and sell them? Like, apart from graphics cards...
Seems odd to me. Most computers I've ever had last for ~10 years, at which point resale value is definitely zero...
So you recover what you spent extra, per the article?
This is an exaggeration, or you're not comparing apples to apples.
The used market for high performance PC gear is quite efficient. You're not going to get a high-end CPU or GPU from the past several years for pennies on the dollar.
Likewise, the resale market for Apple products doesn't guarantee 50% or more unless you're only looking at resale value of very new hardware. For example, you can pick up an M1 Max MacBook Pro (not that old) for closer to 1/3 of the original price.