There are high-schoolers alive today (maybe even in this thread) who were born after Apple stopped charging for updates. Maybe it's time to get some new jokes.
This meme has been doing the rounds for few years now. Also, I don't remember the exact date now when Apple stopped charging for updates. I assume it has been a decent long time since they last did so. The only pain point is Windows which takes the most time to update and has basically made dual booting tougher than ever, thanks to their ever screwing of Grub configs.
Last time they charged for an OS update was with Mountain Lion, which was also the last "big cat" OS. That was in 2012, and it was only 20$. The last OS release that was over 100$ (or even 50$) was Leopard, in 2007, at 130$. Back then, the only way to get it was on a CD, which is obviously much more expensive to manufacture and distribute than a download...